diff --git a/Makefile b/Makefile
index 020be5b5c4..a39be25aa7 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,9 @@ bor:
 protoc:
 	protoc --go_out=. --go-grpc_out=. ./internal/cli/server/proto/*.proto
 
+generate-mocks:
+	go generate mockgen -destination=./tests/bor/mocks/IHeimdallClient.go -package=mocks ./consensus/bor IHeimdallClient
+
 geth:
 	$(GORUN) build/ci.go install ./cmd/geth
 	@echo "Done building."
diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index ac696f446b..2431b5644a 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -78,7 +78,7 @@ type SimulatedBackend struct {
 func NewSimulatedBackendWithDatabase(database ethdb.Database, alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
 	genesis := core.Genesis{Config: params.AllEthashProtocolChanges, GasLimit: gasLimit, Alloc: alloc}
 	genesis.MustCommit(database)
-	blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 
 	backend := &SimulatedBackend{
 		database:   database,
diff --git a/cmd/utils/bor_flags.go b/cmd/utils/bor_flags.go
index 22e1b33d3e..34355532e1 100644
--- a/cmd/utils/bor_flags.go
+++ b/cmd/utils/bor_flags.go
@@ -5,11 +5,12 @@ import (
 	"io/ioutil"
 	"os"
 
+	"gopkg.in/urfave/cli.v1"
+
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
-	"gopkg.in/urfave/cli.v1"
 )
 
 var (
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index e2bbdb17f8..1a593888d6 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -33,6 +33,10 @@ import (
 	"text/template"
 	"time"
 
+	pcsclite "github.com/gballet/go-libpcsclite"
+	gopsutil "github.com/shirou/gopsutil/mem"
+	"gopkg.in/urfave/cli.v1"
+
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 	"github.com/ethereum/go-ethereum/common"
@@ -68,9 +72,6 @@ import (
 	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/params"
-	pcsclite "github.com/gballet/go-libpcsclite"
-	gopsutil "github.com/shirou/gopsutil/mem"
-	"gopkg.in/urfave/cli.v1"
 )
 
 func init() {
@@ -2072,7 +2073,7 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (chain *core.BlockChain, chai
 
 	// TODO(rjl493456442) disable snapshot generation/wiping if the chain is read only.
 	// Disable transaction indexing/unindexing by default.
-	chain, err = core.NewBlockChain(chainDb, cache, config, engine, vmcfg, nil, nil)
+	chain, err = core.NewBlockChain(chainDb, cache, config, engine, vmcfg, nil, nil, nil)
 	if err != nil {
 		Fatalf("Can't create BlockChain: %v", err)
 	}
diff --git a/consensus/bor/bor.go b/consensus/bor/bor.go
index 645fce60bb..dd3cff56fb 100644
--- a/consensus/bor/bor.go
+++ b/consensus/bor/bor.go
@@ -606,7 +606,7 @@ func (c *Bor) verifySeal(chain consensus.ChainHeaderReader, header *types.Header
 		return err
 	}
 
-	if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
+	if !snap.ValidatorSet.HasAddress(signer) {
 		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
 		return &UnauthorizedSignerError{number - 1, signer.Bytes()}
 	}
@@ -623,13 +623,13 @@ func (c *Bor) verifySeal(chain consensus.ChainHeaderReader, header *types.Header
 		parent = chain.GetHeader(header.ParentHash, number-1)
 	}
 
-	if parent != nil && header.Time < parent.Time+CalcProducerDelay(number, succession, c.config) {
+	if IsBlockOnTime(parent, header, number, succession, c.config) {
 		return &BlockTooSoonError{number, succession}
 	}
 
 	// Ensure that the difficulty corresponds to the turn-ness of the signer
 	if !c.fakeDiff {
-		difficulty := snap.Difficulty(signer)
+		difficulty := Difficulty(snap.ValidatorSet, signer)
 		if header.Difficulty.Uint64() != difficulty {
 			return &WrongDifficultyError{number, difficulty, header.Difficulty.Uint64(), signer.Bytes()}
 		}
@@ -638,6 +638,10 @@ func (c *Bor) verifySeal(chain consensus.ChainHeaderReader, header *types.Header
 	return nil
 }
 
+func IsBlockOnTime(parent *types.Header, header *types.Header, number uint64, succession int, cfg *params.BorConfig) bool {
+	return parent != nil && header.Time < parent.Time+CalcProducerDelay(number, succession, cfg)
+}
+
 // Prepare implements consensus.Engine, preparing all the consensus fields of the
 // header for running the transactions on top.
 func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) error {
@@ -653,7 +657,7 @@ func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) e
 	}
 
 	// Set the correct difficulty
-	header.Difficulty = new(big.Int).SetUint64(snap.Difficulty(c.signer))
+	header.Difficulty = new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, c.signer))
 
 	// Ensure the extra data has all it's components
 	if len(header.Extra) < extraVanity {
@@ -716,7 +720,7 @@ func (c *Bor) Finalize(chain consensus.ChainHeaderReader, header *types.Header,
 
 	headerNumber := header.Number.Uint64()
 
-	if headerNumber%c.config.Sprint == 0 {
+	if IsSprintStart(headerNumber, c.config.Sprint) {
 		ctx := context.Background()
 
 		cx := statefull.ChainContext{Chain: chain, Bor: c}
@@ -727,7 +731,7 @@ func (c *Bor) Finalize(chain consensus.ChainHeaderReader, header *types.Header,
 		}
 
 		if c.HeimdallClient != nil {
-			// commit statees
+			// commit states
 			stateSyncData, err = c.CommitStates(ctx, state, header, cx)
 			if err != nil {
 				log.Error("Error while committing states", "error", err)
@@ -790,7 +794,7 @@ func (c *Bor) FinalizeAndAssemble(chain consensus.ChainHeaderReader, header *typ
 
 	headerNumber := header.Number.Uint64()
 
-	if headerNumber%c.config.Sprint == 0 {
+	if IsSprintStart(headerNumber, c.config.Sprint) {
 		ctx := context.Background()
 
 		cx := statefull.ChainContext{Chain: chain, Bor: c}
@@ -867,7 +871,7 @@ func (c *Bor) Seal(chain consensus.ChainHeaderReader, block *types.Block, result
 	}
 
 	// Bail out if we're unauthorized to sign a block
-	if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
+	if !snap.ValidatorSet.HasAddress(signer) {
 		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
 		return &UnauthorizedSignerError{number - 1, signer.Bytes()}
 	}
@@ -945,7 +949,7 @@ func (c *Bor) CalcDifficulty(chain consensus.ChainHeaderReader, _ uint64, parent
 		return nil
 	}
 
-	return new(big.Int).SetUint64(snap.Difficulty(c.signer))
+	return new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, c.signer))
 }
 
 // SealHash returns the hash of a block prior to it being sealed.
@@ -1059,7 +1063,6 @@ func (c *Bor) CommitStates(
 	header *types.Header,
 	chain statefull.ChainContext,
 ) ([]*types.StateSyncData, error) {
-	stateSyncs := make([]*types.StateSyncData, 0)
 	number := header.Number.Uint64()
 
 	_lastStateID, err := c.GenesisContractsClient.LastStateId(number - 1)
@@ -1087,15 +1090,17 @@ func (c *Bor) CommitStates(
 	}
 
 	totalGas := 0 /// limit on gas for state sync per block
-
 	chainID := c.chainConfig.ChainID.String()
+	stateSyncs := make([]*types.StateSyncData, len(eventRecords))
+
+	var gasUsed uint64
 
 	for _, eventRecord := range eventRecords {
 		if eventRecord.ID <= lastStateID {
 			continue
 		}
 
-		if err := validateEventRecord(eventRecord, number, to, lastStateID, chainID); err != nil {
+		if err = validateEventRecord(eventRecord, number, to, lastStateID, chainID); err != nil {
 			log.Error("while validating event record", "block", number, "to", to, "stateID", lastStateID, "error", err.Error())
 			break
 		}
@@ -1109,7 +1114,10 @@ func (c *Bor) CommitStates(
 
 		stateSyncs = append(stateSyncs, &stateData)
 
-		gasUsed, err := c.GenesisContractsClient.CommitState(eventRecord, state, header, chain)
+		// we expect that this call MUST emit an event, otherwise we wouldn't make a receipt
+		// if the receiver address is not a contract then we'll skip the most of the execution and emitting an event as well
+		// https://github.com/maticnetwork/genesis-contracts/blob/master/contracts/StateReceiver.sol#L27
+		gasUsed, err = c.GenesisContractsClient.CommitState(eventRecord, state, header, chain)
 		if err != nil {
 			return nil, err
 		}
diff --git a/consensus/bor/bor_test.go b/consensus/bor/bor_test.go
index 6225532ca9..1e447ba872 100644
--- a/consensus/bor/bor_test.go
+++ b/consensus/bor/bor_test.go
@@ -1,13 +1,15 @@
 package bor
 
 import (
+	"context"
 	"math/big"
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/consensus/bor/heimdall" //nolint:typecheck
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/state"
@@ -55,11 +57,11 @@ func TestGenesisContractChange(t *testing.T) {
 	genesis := genspec.MustCommit(db)
 
 	statedb, err := state.New(genesis.Root(), state.NewDatabase(db), nil)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 
 	config := params.ChainConfig{}
-	chain, err := core.NewBlockChain(db, nil, &config, b, vm.Config{}, nil, nil)
-	assert.NoError(t, err)
+	chain, err := core.NewBlockChain(db, nil, &config, b, vm.Config{}, nil, nil, nil)
+	require.NoError(t, err)
 
 	addBlock := func(root common.Hash, num int64) (common.Hash, *state.StateDB) {
 		h := &types.Header{
@@ -70,37 +72,37 @@ func TestGenesisContractChange(t *testing.T) {
 
 		// write state to database
 		root, err := statedb.Commit(false)
-		assert.NoError(t, err)
-		assert.NoError(t, statedb.Database().TrieDB().Commit(root, true, nil))
+		require.NoError(t, err)
+		require.NoError(t, statedb.Database().TrieDB().Commit(root, true, nil))
 
 		statedb, err := state.New(h.Root, state.NewDatabase(db), nil)
-		assert.NoError(t, err)
+		require.NoError(t, err)
 
 		return root, statedb
 	}
 
-	assert.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x1})
+	require.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x1})
 
 	root := genesis.Root()
 
 	// code does not change
 	root, statedb = addBlock(root, 1)
-	assert.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x1})
+	require.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x1})
 
 	// code changes 1st time
 	root, statedb = addBlock(root, 2)
-	assert.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x2})
+	require.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x2})
 
 	// code same as 1st change
 	root, statedb = addBlock(root, 3)
-	assert.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x2})
+	require.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x2})
 
 	// code changes 2nd time
 	_, statedb = addBlock(root, 4)
-	assert.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x3})
+	require.Equal(t, statedb.GetCode(addr0), []byte{0x1, 0x3})
 
 	// make sure balance change DOES NOT take effect
-	assert.Equal(t, statedb.GetBalance(addr0), big.NewInt(0))
+	require.Equal(t, statedb.GetBalance(addr0), big.NewInt(0))
 }
 
 func TestEncodeSigHeaderJaipur(t *testing.T) {
@@ -124,19 +126,64 @@ func TestEncodeSigHeaderJaipur(t *testing.T) {
 
 	// Jaipur NOT enabled and BaseFee not set
 	hash := SealHash(h, &params.BorConfig{JaipurBlock: 10})
-	assert.Equal(t, hash, hashWithoutBaseFee)
+	require.Equal(t, hash, hashWithoutBaseFee)
 
 	// Jaipur enabled (Jaipur=0) and BaseFee not set
 	hash = SealHash(h, &params.BorConfig{JaipurBlock: 0})
-	assert.Equal(t, hash, hashWithoutBaseFee)
+	require.Equal(t, hash, hashWithoutBaseFee)
 
 	h.BaseFee = big.NewInt(2)
 
 	// Jaipur enabled (Jaipur=Header block) and BaseFee set
 	hash = SealHash(h, &params.BorConfig{JaipurBlock: 1})
-	assert.Equal(t, hash, hashWithBaseFee)
+	require.Equal(t, hash, hashWithBaseFee)
 
 	// Jaipur NOT enabled and BaseFee set
 	hash = SealHash(h, &params.BorConfig{JaipurBlock: 10})
-	assert.Equal(t, hash, hashWithoutBaseFee)
+	require.Equal(t, hash, hashWithoutBaseFee)
+}
+
+// TestCheckpoint can be used for to fetch checkpoint
+// count and checkpoint for debugging purpose.
+// Also, this is kept only for local use.
+func TestCheckpoint(t *testing.T) {
+	t.Skip()
+	t.Parallel()
+
+	ctx := context.Background()
+
+	// TODO: For testing, add heimdall url here
+	h := heimdall.NewHeimdallClient("http://localhost:1317")
+
+	count, err := h.FetchCheckpointCount(ctx)
+	if err != nil {
+		t.Error(err)
+	}
+
+	t.Log("Count:", count)
+
+	checkpoint1, err := h.FetchCheckpoint(ctx, count)
+	if err != nil {
+		t.Error(err)
+	}
+
+	t.Log("Checkpoint1:", checkpoint1)
+
+	checkpoint2, err := h.FetchCheckpoint(ctx, 10000)
+	if err != nil {
+		t.Error(err)
+	}
+
+	t.Log("Checkpoint2:", checkpoint2)
+
+	checkpoint3, err := h.FetchCheckpoint(ctx, -1)
+	if err != nil {
+		t.Error(err)
+	}
+
+	t.Log("Checkpoint3:", checkpoint3)
+
+	if checkpoint3.RootHash != checkpoint1.RootHash {
+		t.Fatal("Invalid root hash")
+	}
 }
diff --git a/consensus/bor/contract/client.go b/consensus/bor/contract/client.go
index dbf3fa0883..9e9e1392dd 100644
--- a/consensus/bor/contract/client.go
+++ b/consensus/bor/contract/client.go
@@ -102,7 +102,8 @@ func (gc *GenesisContractsClient) CommitState(
 
 func (gc *GenesisContractsClient) LastStateId(snapshotNumber uint64) (*big.Int, error) {
 	blockNr := rpc.BlockNumber(snapshotNumber)
-	method := "lastStateId"
+
+	const method = "lastStateId"
 
 	data, err := gc.stateReceiverABI.Pack(method)
 	if err != nil {
diff --git a/consensus/bor/heimdall.go b/consensus/bor/heimdall.go
index e640e47d8a..8934e07cb4 100644
--- a/consensus/bor/heimdall.go
+++ b/consensus/bor/heimdall.go
@@ -12,6 +12,7 @@ import (
 type IHeimdallClient interface {
 	StateSyncEvents(ctx context.Context, fromID uint64, to int64) ([]*clerk.EventRecordWithTime, error)
 	Span(ctx context.Context, spanID uint64) (*span.HeimdallSpan, error)
-	FetchLatestCheckpoint(ctx context.Context) (*checkpoint.Checkpoint, error)
+	FetchCheckpoint(ctx context.Context, number int64) (*checkpoint.Checkpoint, error)
+	FetchCheckpointCount(ctx context.Context) (int64, error)
 	Close()
 }
diff --git a/consensus/bor/heimdall/checkpoint/checkpoint.go b/consensus/bor/heimdall/checkpoint/checkpoint.go
index 77569293ad..3f85f2a233 100644
--- a/consensus/bor/heimdall/checkpoint/checkpoint.go
+++ b/consensus/bor/heimdall/checkpoint/checkpoint.go
@@ -20,3 +20,12 @@ type CheckpointResponse struct {
 	Height string     `json:"height"`
 	Result Checkpoint `json:"result"`
 }
+
+type CheckpointCount struct {
+	Result int64 `json:"result"`
+}
+
+type CheckpointCountResponse struct {
+	Height string          `json:"height"`
+	Result CheckpointCount `json:"result"`
+}
diff --git a/consensus/bor/heimdall/client.go b/consensus/bor/heimdall/client.go
index 64db4a6293..0f17cbc4d4 100644
--- a/consensus/bor/heimdall/client.go
+++ b/consensus/bor/heimdall/client.go
@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"sort"
@@ -59,7 +59,8 @@ func NewHeimdallClient(urlString string) *HeimdallClient {
 const (
 	fetchStateSyncEventsFormat = "from-id=%d&to-time=%d&limit=%d"
 	fetchStateSyncEventsPath   = "clerk/event-record/list"
-	fetchLatestCheckpoint      = "/checkpoints/latest"
+	fetchCheckpoint            = "/checkpoints/%s"
+	fetchCheckpointCount       = "/checkpoints/count"
 
 	fetchSpanFormat = "bor/span/%d"
 )
@@ -115,9 +116,9 @@ func (h *HeimdallClient) Span(ctx context.Context, spanID uint64) (*span.Heimdal
 	return &response.Result, nil
 }
 
-// FetchLatestCheckpoint fetches the latest bor submitted checkpoint from heimdall
-func (h *HeimdallClient) FetchLatestCheckpoint(ctx context.Context) (*checkpoint.Checkpoint, error) {
-	url, err := latestCheckpointURL(h.urlString)
+// FetchCheckpoint fetches the checkpoint from heimdall
+func (h *HeimdallClient) FetchCheckpoint(ctx context.Context, number int64) (*checkpoint.Checkpoint, error) {
+	url, err := checkpointURL(h.urlString, number)
 	if err != nil {
 		return nil, err
 	}
@@ -130,6 +131,21 @@ func (h *HeimdallClient) FetchLatestCheckpoint(ctx context.Context) (*checkpoint
 	return &response.Result, nil
 }
 
+// FetchCheckpointCount fetches the checkpoint count from heimdall
+func (h *HeimdallClient) FetchCheckpointCount(ctx context.Context) (int64, error) {
+	url, err := checkpointCountURL(h.urlString)
+	if err != nil {
+		return 0, err
+	}
+
+	response, err := FetchWithRetry[checkpoint.CheckpointCountResponse](ctx, h.client, url, h.closeCh)
+	if err != nil {
+		return 0, err
+	}
+
+	return response.Result.Result, nil
+}
+
 // FetchWithRetry returns data from heimdall with retry
 func FetchWithRetry[T any](ctx context.Context, client http.Client, url *url.URL, closeCh chan struct{}) (*T, error) {
 	// request data once
@@ -210,8 +226,19 @@ func stateSyncURL(urlString string, fromID uint64, to int64) (*url.URL, error) {
 	return makeURL(urlString, fetchStateSyncEventsPath, queryParams)
 }
 
-func latestCheckpointURL(urlString string) (*url.URL, error) {
-	return makeURL(urlString, fetchLatestCheckpoint, "")
+func checkpointURL(urlString string, number int64) (*url.URL, error) {
+	url := ""
+	if number == -1 {
+		url = fmt.Sprintf(fetchCheckpoint, "latest")
+	} else {
+		url = fmt.Sprintf(fetchCheckpoint, fmt.Sprint(number))
+	}
+
+	return makeURL(urlString, url, "")
+}
+
+func checkpointCountURL(urlString string) (*url.URL, error) {
+	return makeURL(urlString, fetchCheckpointCount, "")
 }
 
 func makeURL(urlString, rawPath, rawQuery string) (*url.URL, error) {
@@ -251,7 +278,7 @@ func internalFetch(ctx context.Context, client http.Client, u *url.URL) ([]byte,
 	}
 
 	// get response
-	body, err := ioutil.ReadAll(res.Body)
+	body, err := io.ReadAll(res.Body)
 	if err != nil {
 		return nil, err
 	}
diff --git a/consensus/bor/heimdall/span/spanner.go b/consensus/bor/heimdall/span/spanner.go
index 1007b19f03..e0f2d66c6b 100644
--- a/consensus/bor/heimdall/span/spanner.go
+++ b/consensus/bor/heimdall/span/spanner.go
@@ -44,7 +44,7 @@ func (c *ChainSpanner) GetCurrentSpan(ctx context.Context, headerHash common.Has
 	blockNr := rpc.BlockNumberOrHashWithHash(headerHash, false)
 
 	// method
-	method := "getCurrentSpan"
+	const method = "getCurrentSpan"
 
 	data, err := c.validatorSet.Pack(method)
 	if err != nil {
diff --git a/consensus/bor/merkle.go b/consensus/bor/merkle.go
index ef1b4eb87e..a2ce1d4023 100644
--- a/consensus/bor/merkle.go
+++ b/consensus/bor/merkle.go
@@ -39,7 +39,7 @@ func convertTo32(input []byte) (output [32]byte) {
 	return
 }
 
-func convert(input []([32]byte)) [][]byte {
+func convert(input [][32]byte) [][]byte {
 	output := make([][]byte, 0, len(input))
 
 	for _, in := range input {
diff --git a/consensus/bor/snapshot.go b/consensus/bor/snapshot.go
index f71ceae0ad..c95031e783 100644
--- a/consensus/bor/snapshot.go
+++ b/consensus/bor/snapshot.go
@@ -131,7 +131,7 @@ func (s *Snapshot) apply(headers []*types.Header) (*Snapshot, error) {
 		}
 
 		// check if signer is in validator set
-		if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
+		if !snap.ValidatorSet.HasAddress(signer) {
 			return nil, &UnauthorizedSignerError{number, signer.Bytes()}
 		}
 
@@ -201,18 +201,18 @@ func (s *Snapshot) signers() []common.Address {
 }
 
 // Difficulty returns the difficulty for a particular signer at the current snapshot number
-func (s *Snapshot) Difficulty(signer common.Address) uint64 {
+func Difficulty(validatorSet *valset.ValidatorSet, signer common.Address) uint64 {
 	// if signer is empty
 	if signer == (common.Address{}) {
 		return 1
 	}
 
-	validators := s.ValidatorSet.Validators
-	proposer := s.ValidatorSet.GetProposer().Address
+	validators := validatorSet.Validators
+	proposer := validatorSet.GetProposer().Address
 	totalValidators := len(validators)
 
-	proposerIndex, _ := s.ValidatorSet.GetByAddress(proposer)
-	signerIndex, _ := s.ValidatorSet.GetByAddress(signer)
+	proposerIndex, _ := validatorSet.GetByAddress(proposer)
+	signerIndex, _ := validatorSet.GetByAddress(signer)
 
 	// temp index
 	tempIndex := signerIndex
diff --git a/consensus/bor/snapshot_test.go b/consensus/bor/snapshot_test.go
index 1a3e967613..de576c18d6 100644
--- a/consensus/bor/snapshot_test.go
+++ b/consensus/bor/snapshot_test.go
@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"pgregory.net/rapid"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -34,7 +34,7 @@ func TestGetSignerSuccessionNumber_ProposerIsSigner(t *testing.T) {
 		t.Fatalf("%s", err)
 	}
 
-	assert.Equal(t, 0, successionNumber)
+	require.Equal(t, 0, successionNumber)
 }
 
 func TestGetSignerSuccessionNumber_SignerIndexIsLarger(t *testing.T) {
@@ -60,7 +60,7 @@ func TestGetSignerSuccessionNumber_SignerIndexIsLarger(t *testing.T) {
 		t.Fatalf("%s", err)
 	}
 
-	assert.Equal(t, signerIndex-proposerIndex, successionNumber)
+	require.Equal(t, signerIndex-proposerIndex, successionNumber)
 }
 
 func TestGetSignerSuccessionNumber_SignerIndexIsSmaller(t *testing.T) {
@@ -82,7 +82,7 @@ func TestGetSignerSuccessionNumber_SignerIndexIsSmaller(t *testing.T) {
 		t.Fatalf("%s", err)
 	}
 
-	assert.Equal(t, signerIndex+numVals-proposerIndex, successionNumber)
+	require.Equal(t, signerIndex+numVals-proposerIndex, successionNumber)
 }
 
 func TestGetSignerSuccessionNumber_ProposerNotFound(t *testing.T) {
@@ -93,6 +93,8 @@ func TestGetSignerSuccessionNumber_ProposerNotFound(t *testing.T) {
 		ValidatorSet: valset.NewValidatorSet(validators),
 	}
 
+	require.Len(t, snap.ValidatorSet.Validators, numVals)
+
 	dummyProposerAddress := randomAddress()
 	snap.ValidatorSet.Proposer = &valset.Validator{Address: dummyProposerAddress}
 
@@ -100,11 +102,11 @@ func TestGetSignerSuccessionNumber_ProposerNotFound(t *testing.T) {
 	signer := snap.ValidatorSet.Validators[3].Address
 
 	_, err := snap.GetSignerSuccessionNumber(signer)
-	assert.NotNil(t, err)
+	require.NotNil(t, err)
 
 	e, ok := err.(*UnauthorizedProposerError)
-	assert.True(t, ok)
-	assert.Equal(t, dummyProposerAddress.Bytes(), e.Proposer)
+	require.True(t, ok)
+	require.Equal(t, dummyProposerAddress.Bytes(), e.Proposer)
 }
 
 func TestGetSignerSuccessionNumber_SignerNotFound(t *testing.T) {
@@ -116,10 +118,10 @@ func TestGetSignerSuccessionNumber_SignerNotFound(t *testing.T) {
 	}
 	dummySignerAddress := randomAddress()
 	_, err := snap.GetSignerSuccessionNumber(dummySignerAddress)
-	assert.NotNil(t, err)
+	require.NotNil(t, err)
 	e, ok := err.(*UnauthorizedSignerError)
-	assert.True(t, ok)
-	assert.Equal(t, dummySignerAddress.Bytes(), e.Signer)
+	require.True(t, ok)
+	require.Equal(t, dummySignerAddress.Bytes(), e.Signer)
 }
 
 // nolint: unparam
diff --git a/consensus/bor/valset/validator.go b/consensus/bor/valset/validator.go
index 250206c1f3..be3f46c830 100644
--- a/consensus/bor/valset/validator.go
+++ b/consensus/bor/valset/validator.go
@@ -47,21 +47,26 @@ func (v *Validator) Cmp(other *Validator) *Validator {
 		return v
 	}
 
-	// nolint:nestif
 	if v.ProposerPriority > other.ProposerPriority {
 		return v
-	} else if v.ProposerPriority < other.ProposerPriority {
-		return other
-	} else {
-		result := bytes.Compare(v.Address.Bytes(), other.Address.Bytes())
-		if result < 0 {
-			return v
-		} else if result > 0 {
-			return other
-		} else {
-			panic("Cannot compare identical validators")
-		}
 	}
+
+	if v.ProposerPriority < other.ProposerPriority {
+		return other
+	}
+
+	result := bytes.Compare(v.Address.Bytes(), other.Address.Bytes())
+
+	if result == 0 {
+		panic("Cannot compare identical validators")
+	}
+
+	if result < 0 {
+		return v
+	}
+
+	// result > 0
+	return other
 }
 
 func (v *Validator) String() string {
diff --git a/consensus/bor/valset/validator_set.go b/consensus/bor/valset/validator_set.go
index 19e6c681fe..772d2c5ef8 100644
--- a/consensus/bor/valset/validator_set.go
+++ b/consensus/bor/valset/validator_set.go
@@ -46,6 +46,7 @@ type ValidatorSet struct {
 
 	// cached (unexported)
 	totalVotingPower int64
+	validatorsMap    map[common.Address]int // address -> index
 }
 
 // NewValidatorSet initializes a ValidatorSet by copying over the
@@ -54,7 +55,7 @@ type ValidatorSet struct {
 // The addresses of validators in `valz` must be unique otherwise the
 // function panics.
 func NewValidatorSet(valz []*Validator) *ValidatorSet {
-	vals := &ValidatorSet{}
+	vals := &ValidatorSet{validatorsMap: make(map[common.Address]int)}
 
 	err := vals.updateWithChangeSet(valz, false)
 	if err != nil {
@@ -232,30 +233,34 @@ func validatorListCopy(valsList []*Validator) []*Validator {
 
 // Copy each validator into a new ValidatorSet.
 func (vals *ValidatorSet) Copy() *ValidatorSet {
+	valCopy := validatorListCopy(vals.Validators)
+	validatorsMap := make(map[common.Address]int, len(vals.Validators))
+
+	for i, val := range valCopy {
+		validatorsMap[val.Address] = i
+	}
+
 	return &ValidatorSet{
 		Validators:       validatorListCopy(vals.Validators),
 		Proposer:         vals.Proposer,
 		totalVotingPower: vals.totalVotingPower,
+		validatorsMap:    validatorsMap,
 	}
 }
 
 // HasAddress returns true if address given is in the validator set, false -
 // otherwise.
-func (vals *ValidatorSet) HasAddress(address []byte) bool {
-	idx := sort.Search(len(vals.Validators), func(i int) bool {
-		return bytes.Compare(address, vals.Validators[i].Address.Bytes()) <= 0
-	})
+func (vals *ValidatorSet) HasAddress(address common.Address) bool {
+	_, ok := vals.validatorsMap[address]
 
-	return idx < len(vals.Validators) && bytes.Equal(vals.Validators[idx].Address.Bytes(), address)
+	return ok
 }
 
 // GetByAddress returns an index of the validator with address and validator
 // itself if found. Otherwise, -1 and nil are returned.
 func (vals *ValidatorSet) GetByAddress(address common.Address) (index int, val *Validator) {
-	idx := sort.Search(len(vals.Validators), func(i int) bool {
-		return bytes.Compare(address.Bytes(), vals.Validators[i].Address.Bytes()) <= 0
-	})
-	if idx < len(vals.Validators) && vals.Validators[idx].Address == address {
+	idx, ok := vals.validatorsMap[address]
+	if ok {
 		return idx, vals.Validators[idx].Copy()
 	}
 
@@ -265,14 +270,14 @@ func (vals *ValidatorSet) GetByAddress(address common.Address) (index int, val *
 // GetByIndex returns the validator's address and validator itself by index.
 // It returns nil values if index is less than 0 or greater or equal to
 // len(ValidatorSet.Validators).
-func (vals *ValidatorSet) GetByIndex(index int) (address []byte, val *Validator) {
+func (vals *ValidatorSet) GetByIndex(index int) (address common.Address, val *Validator) {
 	if index < 0 || index >= len(vals.Validators) {
-		return nil, nil
+		return common.Address{}, nil
 	}
 
 	val = vals.Validators[index]
 
-	return val.Address.Bytes(), val.Copy()
+	return val.Address, val.Copy()
 }
 
 // Size returns the length of the validator set.
@@ -328,7 +333,7 @@ func (vals *ValidatorSet) GetProposer() (proposer *Validator) {
 func (vals *ValidatorSet) findProposer() *Validator {
 	var proposer *Validator
 	for _, val := range vals.Validators {
-		if proposer == nil || !bytes.Equal(val.Address.Bytes(), proposer.Address.Bytes()) {
+		if proposer == nil || val.Address != proposer.Address {
 			proposer = proposer.Cmp(val)
 		}
 	}
@@ -371,14 +376,19 @@ func processChanges(origChanges []*Validator) (updates, removals []*Validator, e
 	changes := validatorListCopy(origChanges)
 	sort.Sort(ValidatorsByAddress(changes))
 
-	removals = make([]*Validator, 0, len(changes))
-	updates = make([]*Validator, 0, len(changes))
+	sliceCap := len(changes) / 2
+	if sliceCap == 0 {
+		sliceCap = 1
+	}
+
+	removals = make([]*Validator, 0, sliceCap)
+	updates = make([]*Validator, 0, sliceCap)
 
 	var prevAddr common.Address
 
 	// Scan changes by address and append valid validators to updates or removals lists.
 	for _, valUpdate := range changes {
-		if bytes.Equal(valUpdate.Address.Bytes(), prevAddr.Bytes()) {
+		if valUpdate.Address == prevAddr {
 			err = fmt.Errorf("duplicate entry %v in %v", valUpdate, changes)
 			return nil, nil, err
 		}
@@ -489,10 +499,11 @@ func (vals *ValidatorSet) applyUpdates(updates []*Validator) {
 		} else {
 			// Apply add or update.
 			merged[i] = updates[0]
-			if bytes.Equal(existing[0].Address.Bytes(), updates[0].Address.Bytes()) {
+			if existing[0].Address == updates[0].Address {
 				// Validator is present in both, advance existing.
 				existing = existing[1:]
 			}
+
 			updates = updates[1:]
 		}
 		i++
@@ -503,6 +514,7 @@ func (vals *ValidatorSet) applyUpdates(updates []*Validator) {
 		merged[i] = existing[j]
 		i++
 	}
+
 	// OR add updates which are left.
 	for j := 0; j < len(updates); j++ {
 		merged[i] = updates[j]
@@ -541,7 +553,7 @@ func (vals *ValidatorSet) applyRemovals(deletes []*Validator) {
 
 	// Loop over deletes until we removed all of them.
 	for len(deletes) > 0 {
-		if bytes.Equal(existing[0].Address.Bytes(), deletes[0].Address.Bytes()) {
+		if existing[0].Address == deletes[0].Address {
 			deletes = deletes[1:]
 		} else { // Leave it in the resulting slice.
 			merged[i] = existing[0]
@@ -599,8 +611,7 @@ func (vals *ValidatorSet) updateWithChangeSet(changes []*Validator, allowDeletes
 	computeNewPriorities(updates, vals, updatedTotalVotingPower)
 
 	// Apply updates and removals.
-	vals.applyUpdates(updates)
-	vals.applyRemovals(deletes)
+	vals.updateValidators(updates, deletes)
 
 	if err := vals.UpdateTotalVotingPower(); err != nil {
 		return err
@@ -613,6 +624,17 @@ func (vals *ValidatorSet) updateWithChangeSet(changes []*Validator, allowDeletes
 	return nil
 }
 
+func (vals *ValidatorSet) updateValidators(updates []*Validator, deletes []*Validator) {
+	vals.applyUpdates(updates)
+	vals.applyRemovals(deletes)
+
+	vals.validatorsMap = make(map[common.Address]int, len(vals.Validators))
+
+	for i, val := range vals.Validators {
+		vals.validatorsMap[val.Address] = i
+	}
+}
+
 // UpdateWithChangeSet attempts to update the validator set with 'changes'.
 // It performs the following steps:
 // - validates the changes making sure there are no duplicates and splits them in updates and deletes
@@ -661,7 +683,7 @@ func (vals *ValidatorSet) StringIndented(indent string) string {
 		return "nil-ValidatorSet"
 	}
 
-	var valStrings []string
+	valStrings := make([]string, 0, len(vals.Validators))
 
 	vals.Iterate(func(index int, val *Validator) bool {
 		valStrings = append(valStrings, val.String())
diff --git a/consensus/bor/valset/validator_set_test.go b/consensus/bor/valset/validator_set_test.go
new file mode 100644
index 0000000000..9397ca3e92
--- /dev/null
+++ b/consensus/bor/valset/validator_set_test.go
@@ -0,0 +1,199 @@
+package valset
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gotest.tools/assert"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+func NewValidatorFromKey(key string, votingPower int64) *Validator {
+	privKey, _ := crypto.HexToECDSA(key)
+
+	return NewValidator(crypto.PubkeyToAddress(privKey.PublicKey), votingPower)
+}
+
+func GetValidators() [4]*Validator {
+	const (
+		// addr0 = 0x96C42C56fdb78294F96B0cFa33c92bed7D75F96a
+		signer0 = "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd9"
+
+		// addr1 = 0x98925BE497f6dFF6A5a33dDA8B5933cA35262d69
+		signer1 = "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd8"
+
+		//addr2 = 0x648Cf2A5b119E2c04061021834F8f75735B1D36b
+		signer2 = "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd7"
+
+		//addr3 = 0x168f220B3b313D456eD4797520eFdFA9c57E6C45
+		signer3 = "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd6"
+	)
+
+	return [4]*Validator{
+		NewValidatorFromKey(signer0, 100),
+		NewValidatorFromKey(signer1, 200),
+		NewValidatorFromKey(signer2, 300),
+		NewValidatorFromKey(signer3, 400),
+	}
+}
+
+func TestIncrementProposerPriority(t *testing.T) {
+	t.Parallel()
+
+	vals := GetValidators()
+
+	// Validator set length = 1
+	valSet := NewValidatorSet(vals[:1])
+
+	expectedPropsers := []*Validator{vals[0], vals[0], vals[0], vals[0], vals[0], vals[0], vals[0], vals[0], vals[0], vals[0]}
+
+	for i := 0; i < 10; i++ {
+		valSet.IncrementProposerPriority(1)
+
+		require.Equal(t, expectedPropsers[i].Address, valSet.GetProposer().Address)
+	}
+
+	// Validator set length = 2
+	valSet = NewValidatorSet(vals[:2])
+
+	expectedPropsers = []*Validator{vals[0], vals[1], vals[1], vals[0], vals[1], vals[1], vals[0], vals[1], vals[1], vals[0]}
+
+	for i := 0; i < 10; i++ {
+		valSet.IncrementProposerPriority(1)
+
+		require.Equal(t, expectedPropsers[i].Address, valSet.GetProposer().Address)
+	}
+
+	// Validator set length = 3
+	valSet = NewValidatorSet(vals[:3])
+
+	expectedPropsers = []*Validator{vals[1], vals[2], vals[0], vals[1], vals[2], vals[2], vals[1], vals[2], vals[0], vals[1]}
+
+	for i := 0; i < 10; i++ {
+		valSet.IncrementProposerPriority(1)
+
+		require.Equal(t, expectedPropsers[i].Address, valSet.GetProposer().Address)
+	}
+
+	// Validator set length = 4
+	valSet = NewValidatorSet(vals[:4])
+
+	expectedPropsers = []*Validator{vals[2], vals[1], vals[3], vals[2], vals[0], vals[3], vals[1], vals[2], vals[3], vals[3]}
+
+	for i := 0; i < 10; i++ {
+		valSet.IncrementProposerPriority(1)
+
+		require.Equal(t, expectedPropsers[i].Address, valSet.GetProposer().Address)
+	}
+}
+
+func TestRescalePriorities(t *testing.T) {
+	t.Parallel()
+
+	vals := GetValidators()
+
+	// Validator set length = 1
+	valSet := NewValidatorSet(vals[:1])
+
+	valSet.RescalePriorities(10)
+
+	expectedPriorities := []int64{0}
+	for i, val := range valSet.Validators {
+		require.Equal(t, expectedPriorities[i], val.ProposerPriority)
+	}
+
+	// Validator set length = 2
+
+	valSet = NewValidatorSet(vals[:2])
+
+	valSet.RescalePriorities(100)
+
+	expectedPriorities = []int64{50, -50}
+	for i, val := range valSet.Validators {
+		require.Equal(t, expectedPriorities[i], val.ProposerPriority)
+	}
+
+	// Validator set length = 3
+
+	valSet = NewValidatorSet(vals[:3])
+
+	valSet.RescalePriorities(30)
+
+	expectedPriorities = []int64{-17, 5, 11}
+	for i, val := range valSet.Validators {
+		require.Equal(t, expectedPriorities[i], val.ProposerPriority)
+	}
+
+	// Validator set length = 4
+
+	valSet = NewValidatorSet(vals[:4])
+
+	valSet.RescalePriorities(10)
+
+	expectedPriorities = []int64{-6, 3, 1, 2}
+	for i, val := range valSet.Validators {
+		require.Equal(t, expectedPriorities[i], val.ProposerPriority)
+	}
+}
+
+func TestGetValidatorByAddressAndIndex(t *testing.T) {
+	t.Parallel()
+
+	vals := GetValidators()
+	valSet := NewValidatorSet(vals[:4])
+
+	for _, val := range valSet.Validators {
+		idx, valByAddress := valSet.GetByAddress(val.Address)
+		addr, valByIndex := valSet.GetByIndex(idx)
+
+		assert.DeepEqual(t, val, valByIndex)
+		assert.DeepEqual(t, val, valByAddress)
+		assert.DeepEqual(t, val.Address, addr)
+	}
+
+	tempAddress := common.HexToAddress("0x12345")
+
+	// Negative Testcase
+	idx, _ := valSet.GetByAddress(tempAddress)
+	require.Equal(t, idx, -1)
+
+	// checking for validator index out of range
+	addr, _ := valSet.GetByIndex(100)
+	require.Equal(t, addr, common.Address{})
+}
+
+func TestUpdateWithChangeSet(t *testing.T) {
+	t.Parallel()
+
+	vals := GetValidators()
+	valSet := NewValidatorSet(vals[:4])
+
+	// halved the power of vals[2] and doubled the power of vals[3]
+	vals[2].VotingPower = 150
+	vals[3].VotingPower = 800
+
+	// Adding new temp validator in the set
+	const tempSigner = "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd5"
+
+	tempVal := NewValidatorFromKey(tempSigner, 250)
+
+	// check totalVotingPower before updating validator set
+	require.Equal(t, int64(1000), valSet.TotalVotingPower())
+
+	err := valSet.UpdateWithChangeSet([]*Validator{vals[2], vals[3], tempVal})
+	require.NoError(t, err)
+
+	// check totalVotingPower after updating validator set
+	require.Equal(t, int64(1500), valSet.TotalVotingPower())
+
+	_, updatedVal2 := valSet.GetByAddress(vals[2].Address)
+	require.Equal(t, int64(150), updatedVal2.VotingPower)
+
+	_, updatedVal3 := valSet.GetByAddress(vals[3].Address)
+	require.Equal(t, int64(800), updatedVal3.VotingPower)
+
+	_, updatedTempVal := valSet.GetByAddress(tempVal.Address)
+	require.Equal(t, int64(250), updatedTempVal.VotingPower)
+}
diff --git a/consensus/clique/clique_test.go b/consensus/clique/clique_test.go
index 1bd32acd37..b2850587ea 100644
--- a/consensus/clique/clique_test.go
+++ b/consensus/clique/clique_test.go
@@ -55,7 +55,7 @@ func TestReimportMirroredState(t *testing.T) {
 	genesis := genspec.MustCommit(db)
 
 	// Generate a batch of blocks, each properly signed
-	chain, _ := core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	blocks, _ := core.GenerateChain(params.AllCliqueProtocolChanges, genesis, engine, db, 3, func(i int, block *core.BlockGen) {
@@ -89,7 +89,7 @@ func TestReimportMirroredState(t *testing.T) {
 	db = rawdb.NewMemoryDatabase()
 	genspec.MustCommit(db)
 
-	chain, _ = core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, _ = core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	if _, err := chain.InsertChain(blocks[:2]); err != nil {
@@ -102,7 +102,7 @@ func TestReimportMirroredState(t *testing.T) {
 	// Simulate a crash by creating a new chain on top of the database, without
 	// flushing the dirty states out. Insert the last block, triggering a sidechain
 	// reimport.
-	chain, _ = core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, _ = core.NewBlockChain(db, nil, params.AllCliqueProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	if _, err := chain.InsertChain(blocks[2:]); err != nil {
diff --git a/consensus/clique/snapshot_test.go b/consensus/clique/snapshot_test.go
index 094868ca74..54621718e0 100644
--- a/consensus/clique/snapshot_test.go
+++ b/consensus/clique/snapshot_test.go
@@ -450,7 +450,7 @@ func TestClique(t *testing.T) {
 			batches[len(batches)-1] = append(batches[len(batches)-1], block)
 		}
 		// Pass all the headers through clique and ensure tallying succeeds
-		chain, err := core.NewBlockChain(db, nil, &config, engine, vm.Config{}, nil, nil)
+		chain, err := core.NewBlockChain(db, nil, &config, engine, vm.Config{}, nil, nil, nil)
 		if err != nil {
 			t.Errorf("test %d: failed to create test chain: %v", i, err)
 			continue
diff --git a/core/bench_test.go b/core/bench_test.go
index ad6179d0a8..3d4cf31a4e 100644
--- a/core/bench_test.go
+++ b/core/bench_test.go
@@ -201,7 +201,7 @@ func benchInsertChain(b *testing.B, disk bool, gen func(int, *BlockGen)) {
 
 	// Time the insertion of the new chain.
 	// State and blocks are stored in the same DB.
-	chainman, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	chainman, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer chainman.Stop()
 	b.ReportAllocs()
 	b.ResetTimer()
@@ -317,7 +317,8 @@ func benchReadChain(b *testing.B, full bool, count uint64) {
 		if err != nil {
 			b.Fatalf("error opening database at %v: %v", dir, err)
 		}
-		chain, err := NewBlockChain(db, &cacheConfig, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+
+		chain, err := NewBlockChain(db, &cacheConfig, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		if err != nil {
 			b.Fatalf("error creating chain: %v", err)
 		}
diff --git a/core/block_validator_test.go b/core/block_validator_test.go
index 0f183ba527..c777d31c4a 100644
--- a/core/block_validator_test.go
+++ b/core/block_validator_test.go
@@ -49,7 +49,7 @@ func TestHeaderVerification(t *testing.T) {
 		headers[i] = block.Header()
 	}
 	// Run the header checker for blocks one-by-one, checking for both valid and invalid nonces
-	chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+	chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	for i := 0; i < len(blocks); i++ {
@@ -168,7 +168,7 @@ func testHeaderVerificationForMerging(t *testing.T, isClique bool) {
 		t.Logf("Log header after the merging %d: %v", block.NumberU64(), string(blob))
 	}
 	// Run the header checker for blocks one-by-one, checking for both valid and invalid nonces
-	chain, _ := NewBlockChain(testdb, nil, chainConfig, runEngine, vm.Config{}, nil, nil)
+	chain, _ := NewBlockChain(testdb, nil, chainConfig, runEngine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	// Verify the blocks before the merging
@@ -279,11 +279,11 @@ func testHeaderConcurrentVerification(t *testing.T, threads int) {
 		var results <-chan error
 
 		if valid {
-			chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+			chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 			_, results = chain.engine.VerifyHeaders(chain, headers, seals)
 			chain.Stop()
 		} else {
-			chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFakeFailer(uint64(len(headers)-1)), vm.Config{}, nil, nil)
+			chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFakeFailer(uint64(len(headers)-1)), vm.Config{}, nil, nil, nil)
 			_, results = chain.engine.VerifyHeaders(chain, headers, seals)
 			chain.Stop()
 		}
@@ -346,7 +346,7 @@ func testHeaderConcurrentAbortion(t *testing.T, threads int) {
 	defer runtime.GOMAXPROCS(old)
 
 	// Start the verifications and immediately abort
-	chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFakeDelayer(time.Millisecond), vm.Config{}, nil, nil)
+	chain, _ := NewBlockChain(testdb, nil, params.TestChainConfig, ethash.NewFakeDelayer(time.Millisecond), vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	abort, results := chain.engine.VerifyHeaders(chain, headers, seals)
diff --git a/core/blockchain.go b/core/blockchain.go
index 8a4c581f66..fe8172e41e 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -29,6 +29,7 @@ import (
 
 	lru "github.com/hashicorp/golang-lru"
 
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/mclock"
 	"github.com/ethereum/go-ethereum/common/prque"
@@ -38,6 +39,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/state/snapshot"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/eth/downloader/whitelist"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/internal/syncx"
@@ -221,7 +223,8 @@ type BlockChain struct {
 // NewBlockChain returns a fully initialised block chain using information
 // available in the database. It initialises the default Ethereum Validator
 // and Processor.
-func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config, shouldPreserve func(header *types.Header) bool, txLookupLimit *uint64) (*BlockChain, error) {
+//nolint:gocognit
+func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *params.ChainConfig, engine consensus.Engine, vmConfig vm.Config, shouldPreserve func(header *types.Header) bool, txLookupLimit *uint64, checker ethereum.ChainValidator) (*BlockChain, error) {
 	if cacheConfig == nil {
 		cacheConfig = DefaultCacheConfig
 	}
@@ -257,7 +260,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 
 		borReceiptsCache: borReceiptsCache,
 	}
-	bc.forker = NewForkChoice(bc, shouldPreserve)
+	bc.forker = NewForkChoice(bc, shouldPreserve, checker)
 	bc.validator = NewBlockValidator(chainConfig, bc, engine)
 	bc.prefetcher = newStatePrefetcher(chainConfig, bc, engine)
 	bc.processor = NewStateProcessor(chainConfig, bc, engine)
@@ -908,6 +911,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 		ancientBlocks, liveBlocks     types.Blocks
 		ancientReceipts, liveReceipts []types.Receipts
 	)
+
 	// Do a sanity check that the provided chain is actually ordered and linked
 	for i := 0; i < len(blockChain); i++ {
 		if i != 0 {
@@ -933,7 +937,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 
 	// updateHead updates the head fast sync block if the inserted blocks are better
 	// and returns an indicator whether the inserted blocks are canonical.
-	updateHead := func(head *types.Block) bool {
+	updateHead := func(head *types.Block, headers []*types.Header) bool {
 		if !bc.chainmu.TryLock() {
 			return false
 		}
@@ -948,6 +952,14 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 			} else if !reorg {
 				return false
 			}
+
+			isValid, err := bc.forker.ValidateReorg(bc.CurrentFastBlock().Header(), headers)
+			if err != nil {
+				log.Warn("Reorg failed", "err", err)
+				return false
+			} else if !isValid {
+				return false
+			}
 			rawdb.WriteHeadFastBlockHash(bc.db, head.Hash())
 			bc.currentFastBlock.Store(head)
 			headFastBlockGauge.Update(int64(head.NumberU64()))
@@ -985,10 +997,14 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 			return 0, fmt.Errorf("containing header #%d [%x..] unknown", last.Number(), last.Hash().Bytes()[:4])
 		}
 
-		// BOR: Retrieve all the bor receipts.
+		// BOR: Retrieve all the bor receipts and also maintain the array of headers
+		// for bor specific reorg check.
 		borReceipts := []types.Receipts{}
+
+		var headers []*types.Header
 		for _, block := range blockChain {
 			borReceipts = append(borReceipts, []*types.Receipt{bc.GetBorReceiptByHash(block.Hash())})
+			headers = append(headers, block.Header())
 		}
 
 		// Write all chain data to ancients.
@@ -1039,7 +1055,7 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 		}
 		// Update the current fast block because all block data is now present in DB.
 		previousFastBlock := bc.CurrentFastBlock().NumberU64()
-		if !updateHead(blockChain[len(blockChain)-1]) {
+		if !updateHead(blockChain[len(blockChain)-1], headers) {
 			// We end up here if the header chain has reorg'ed, and the blocks/receipts
 			// don't match the canonical chain.
 			if err := bc.db.TruncateHead(previousFastBlock + 1); err != nil {
@@ -1075,7 +1091,11 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 	writeLive := func(blockChain types.Blocks, receiptChain []types.Receipts) (int, error) {
 		skipPresenceCheck := false
 		batch := bc.db.NewBatch()
+		headers := make([]*types.Header, 0, len(blockChain))
 		for i, block := range blockChain {
+			// Update the headers for bor specific reorg check
+			headers = append(headers, block.Header())
+
 			// Short circuit insertion if shutting down or processing failed
 			if bc.insertStopped() {
 				return 0, errInsertionInterrupted
@@ -1122,7 +1142,8 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 				return 0, err
 			}
 		}
-		updateHead(blockChain[len(blockChain)-1])
+
+		updateHead(blockChain[len(blockChain)-1], headers)
 		return 0, nil
 	}
 
@@ -1491,6 +1512,18 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals, setHead bool)
 	it := newInsertIterator(chain, results, bc.validator)
 	block, err := it.next()
 
+	// Check the validity of incoming chain
+	isValid, err1 := bc.forker.ValidateReorg(bc.CurrentBlock().Header(), headers)
+	if err1 != nil {
+		return it.index, err1
+	}
+
+	if !isValid {
+		// The chain to be imported is invalid as the blocks doesn't match with
+		// the whitelisted checkpoints.
+		return it.index, whitelist.ErrCheckpointMismatch
+	}
+
 	// Left-trim all the known blocks that don't need to build snapshot
 	if bc.skipBlock(err, it) {
 		// First block (and state) is known
@@ -1833,6 +1866,7 @@ func (bc *BlockChain) insertSideChain(block *types.Block, it *insertIterator) (i
 		externTd  *big.Int
 		lastBlock = block
 		current   = bc.CurrentBlock()
+		headers   []*types.Header
 	)
 	// The first sidechain block error is already verified to be ErrPrunedAncestor.
 	// Since we don't import them here, we expect ErrUnknownAncestor for the remaining
@@ -1840,6 +1874,7 @@ func (bc *BlockChain) insertSideChain(block *types.Block, it *insertIterator) (i
 	// to disk.
 	err := consensus.ErrPrunedAncestor
 	for ; block != nil && errors.Is(err, consensus.ErrPrunedAncestor); block, err = it.next() {
+		headers = append(headers, block.Header())
 		// Check the canonical state root for that number
 		if number := block.NumberU64(); current.NumberU64() >= number {
 			canonical := bc.GetBlockByNumber(number)
@@ -1895,7 +1930,13 @@ func (bc *BlockChain) insertSideChain(block *types.Block, it *insertIterator) (i
 	if err != nil {
 		return it.index, err
 	}
-	if !reorg {
+
+	isValid, err := bc.forker.ValidateReorg(current.Header(), headers)
+	if err != nil {
+		return it.index, err
+	}
+
+	if !reorg || !isValid {
 		localTd := bc.GetTd(current.Hash(), current.NumberU64())
 		log.Info("Sidechain written to disk", "start", it.first().NumberU64(), "end", it.previous().Number, "sidetd", externTd, "localtd", localTd)
 		return it.index, err
diff --git a/core/blockchain_bor_test.go b/core/blockchain_bor_test.go
index 1b0373c41a..6bc38ec4ab 100644
--- a/core/blockchain_bor_test.go
+++ b/core/blockchain_bor_test.go
@@ -27,7 +27,7 @@ func TestChain2HeadEvent(t *testing.T) {
 		signer  = types.LatestSigner(gspec.Config)
 	)
 
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	chain2HeadCh := make(chan Chain2HeadEvent, 64)
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index de97000918..b2c14f81ba 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -59,7 +59,7 @@ func newCanonical(engine consensus.Engine, n int, full bool) (ethdb.Database, *B
 	)
 
 	// Initialize a fresh chain with only a genesis block
-	blockchain, _ := NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	// Create and inject the requested chain
 	if n == 0 {
 		return db, blockchain, nil
@@ -655,7 +655,7 @@ func testReorgBadHashes(t *testing.T, full bool) {
 	blockchain.Stop()
 
 	// Create a new BlockChain and check that it rolled back the state.
-	ncm, err := NewBlockChain(blockchain.db, nil, blockchain.chainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+	ncm, err := NewBlockChain(blockchain.db, nil, blockchain.chainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create new chain manager: %v", err)
 	}
@@ -768,7 +768,7 @@ func TestFastVsFullChains(t *testing.T) {
 	// Import the chain as an archive node for the comparison baseline
 	archiveDb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(archiveDb)
-	archive, _ := NewBlockChain(archiveDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	archive, _ := NewBlockChain(archiveDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer archive.Stop()
 
 	if n, err := archive.InsertChain(blocks); err != nil {
@@ -777,7 +777,7 @@ func TestFastVsFullChains(t *testing.T) {
 	// Fast import the chain as a non-archive node to test
 	fastDb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(fastDb)
-	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer fast.Stop()
 
 	headers := make([]*types.Header, len(blocks))
@@ -801,7 +801,7 @@ func TestFastVsFullChains(t *testing.T) {
 		t.Fatalf("failed to create temp freezer db: %v", err)
 	}
 	gspec.MustCommit(ancientDb)
-	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer ancient.Stop()
 
 	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
@@ -923,7 +923,7 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	archiveCaching := *DefaultCacheConfig
 	archiveCaching.TrieDirtyDisabled = true
 
-	archive, _ := NewBlockChain(archiveDb, &archiveCaching, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	archive, _ := NewBlockChain(archiveDb, &archiveCaching, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if n, err := archive.InsertChain(blocks); err != nil {
 		t.Fatalf("failed to process block %d: %v", n, err)
 	}
@@ -936,7 +936,8 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	// Import the chain as a non-archive node and ensure all pointers are updated
 	fastDb, delfn := makeDb()
 	defer delfn()
-	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+
+	fast, _ := NewBlockChain(fastDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer fast.Stop()
 
 	headers := make([]*types.Header, len(blocks))
@@ -956,7 +957,8 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	// Import the chain as a ancient-first node and ensure all pointers are updated
 	ancientDb, delfn := makeDb()
 	defer delfn()
-	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer ancient.Stop()
 
 	if n, err := ancient.InsertHeaderChain(headers, 1); err != nil {
@@ -975,7 +977,8 @@ func TestLightVsFastVsFullChainHeads(t *testing.T) {
 	// Import the chain as a light node and ensure all pointers are updated
 	lightDb, delfn := makeDb()
 	defer delfn()
-	light, _ := NewBlockChain(lightDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+
+	light, _ := NewBlockChain(lightDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if n, err := light.InsertHeaderChain(headers, 1); err != nil {
 		t.Fatalf("failed to insert header %d: %v", n, err)
 	}
@@ -1044,7 +1047,7 @@ func TestChainTxReorgs(t *testing.T) {
 		}
 	})
 	// Import the chain. This runs all block validation rules.
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if i, err := blockchain.InsertChain(chain); err != nil {
 		t.Fatalf("failed to insert original chain[%d]: %v", i, err)
 	}
@@ -1114,7 +1117,7 @@ func TestLogReorgs(t *testing.T) {
 		signer  = types.LatestSigner(gspec.Config)
 	)
 
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	rmLogsCh := make(chan RemovedLogsEvent)
@@ -1167,7 +1170,7 @@ func TestLogRebirth(t *testing.T) {
 		genesis       = gspec.MustCommit(db)
 		signer        = types.LatestSigner(gspec.Config)
 		engine        = ethash.NewFaker()
-		blockchain, _ = NewBlockChain(db, nil, gspec.Config, engine, vm.Config{}, nil, nil)
+		blockchain, _ = NewBlockChain(db, nil, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	)
 
 	defer blockchain.Stop()
@@ -1230,7 +1233,7 @@ func TestSideLogRebirth(t *testing.T) {
 		gspec         = &Genesis{Config: params.TestChainConfig, Alloc: GenesisAlloc{addr1: {Balance: big.NewInt(10000000000000000)}}}
 		genesis       = gspec.MustCommit(db)
 		signer        = types.LatestSigner(gspec.Config)
-		blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+		blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	)
 
 	defer blockchain.Stop()
@@ -1305,7 +1308,7 @@ func TestReorgSideEvent(t *testing.T) {
 		signer  = types.LatestSigner(gspec.Config)
 	)
 
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {})
@@ -1437,7 +1440,7 @@ func TestEIP155Transition(t *testing.T) {
 		genesis = gspec.MustCommit(db)
 	)
 
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	blocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 4, func(i int, block *BlockGen) {
@@ -1545,7 +1548,8 @@ func TestEIP161AccountRemoval(t *testing.T) {
 		}
 		genesis = gspec.MustCommit(db)
 	)
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	blocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, block *BlockGen) {
@@ -1620,7 +1624,7 @@ func TestBlockchainHeaderchainReorgConsistency(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -1664,7 +1668,7 @@ func TestTrieForkGC(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -1703,7 +1707,7 @@ func TestLargeReorgTrieGC(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -1764,7 +1768,7 @@ func TestBlockchainRecovery(t *testing.T) {
 		t.Fatalf("failed to create temp freezer db: %v", err)
 	}
 	gspec.MustCommit(ancientDb)
-	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	ancient, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 
 	headers := make([]*types.Header, len(blocks))
 	for i, block := range blocks {
@@ -1784,7 +1788,7 @@ func TestBlockchainRecovery(t *testing.T) {
 	rawdb.WriteHeadFastBlockHash(ancientDb, midBlock.Hash())
 
 	// Reopen broken blockchain again
-	ancient, _ = NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	ancient, _ = NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer ancient.Stop()
 	if num := ancient.CurrentBlock().NumberU64(); num != 0 {
 		t.Errorf("head block mismatch: have #%v, want #%v", num, 0)
@@ -1836,7 +1840,7 @@ func TestInsertReceiptChainRollback(t *testing.T) {
 	}
 	gspec := Genesis{Config: params.AllEthashProtocolChanges}
 	gspec.MustCommit(ancientDb)
-	ancientChain, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	ancientChain, _ := NewBlockChain(ancientDb, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer ancientChain.Stop()
 
 	// Import the canonical header chain.
@@ -1897,7 +1901,7 @@ func TestLowDiffLongChain(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -1963,7 +1967,7 @@ func testSideImport(t *testing.T, numCanonBlocksInSidechain, blocksBetweenCommon
 	// Generate and import the canonical chain
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(diskdb)
-	chain, err := NewBlockChain(diskdb, nil, &chainConfig, runEngine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, &chainConfig, runEngine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2102,7 +2106,7 @@ func testInsertKnownChainData(t *testing.T, typ string) {
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(chaindb)
 	defer os.RemoveAll(dir)
 
-	chain, err := NewBlockChain(chaindb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(chaindb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2266,7 +2270,7 @@ func testInsertKnownChainDataWithMerging(t *testing.T, typ string, mergeHeight i
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(chaindb)
 	defer os.RemoveAll(dir)
 
-	chain, err := NewBlockChain(chaindb, nil, &chainConfig, runEngine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(chaindb, nil, &chainConfig, runEngine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2384,7 +2388,7 @@ func getLongAndShortChains() (bc *BlockChain, longChain []*types.Block, heavyCha
 	diskdb := rawdb.NewMemoryDatabase()
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		return nil, nil, nil, fmt.Errorf("failed to create tester chain: %v", err)
 	}
@@ -2577,7 +2581,7 @@ func TestTransactionIndices(t *testing.T) {
 
 	// Import all blocks into ancient db
 	l := uint64(0)
-	chain, err := NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l)
+	chain, err := NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2602,7 +2606,7 @@ func TestTransactionIndices(t *testing.T) {
 			t.Fatalf("failed to create temp freezer db: %v", err)
 		}
 		gspec.MustCommit(ancientDb)
-		chain, err = NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l)
+		chain, err = NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l, nil)
 		if err != nil {
 			t.Fatalf("failed to create tester chain: %v", err)
 		}
@@ -2626,7 +2630,7 @@ func TestTransactionIndices(t *testing.T) {
 	limit = []uint64{0, 64 /* drop stale */, 32 /* shorten history */, 64 /* extend history */, 0 /* restore all */}
 	tails := []uint64{0, 67 /* 130 - 64 + 1 */, 100 /* 131 - 32 + 1 */, 69 /* 132 - 64 + 1 */, 0}
 	for i, l := range limit {
-		chain, err = NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l)
+		chain, err = NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l, nil)
 		if err != nil {
 			t.Fatalf("failed to create tester chain: %v", err)
 		}
@@ -2704,7 +2708,7 @@ func TestSkipStaleTxIndicesInSnapSync(t *testing.T) {
 
 	// Import all blocks into ancient db, only HEAD-32 indices are kept.
 	l := uint64(32)
-	chain, err := NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l)
+	chain, err := NewBlockChain(ancientDb, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, &l, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2768,7 +2772,7 @@ func benchmarkLargeNumberOfValueToNonexisting(b *testing.B, numTxs, numBlocks in
 		diskdb := rawdb.NewMemoryDatabase()
 		gspec.MustCommit(diskdb)
 
-		chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+		chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 		if err != nil {
 			b.Fatalf("failed to create tester chain: %v", err)
 		}
@@ -2851,7 +2855,7 @@ func TestSideImportPrunedBlocks(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 
 	(&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(diskdb)
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -2945,7 +2949,7 @@ func TestDeleteCreateRevert(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3059,7 +3063,7 @@ func TestDeleteRecreateSlots(t *testing.T) {
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{
 		Debug:  true,
 		Tracer: logger.NewJSONLogger(nil, os.Stdout),
-	}, nil, nil)
+	}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3139,7 +3143,7 @@ func TestDeleteRecreateAccount(t *testing.T) {
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{
 		Debug:  true,
 		Tracer: logger.NewJSONLogger(nil, os.Stdout),
-	}, nil, nil)
+	}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3312,7 +3316,7 @@ func TestDeleteRecreateSlotsAcrossManyBlocks(t *testing.T) {
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{
 		//Debug:  true,
 		//Tracer: vm.NewJSONLogger(nil, os.Stdout),
-	}, nil, nil)
+	}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3446,7 +3450,7 @@ func TestInitThenFailCreateContract(t *testing.T) {
 	chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{
 		//Debug:  true,
 		//Tracer: vm.NewJSONLogger(nil, os.Stdout),
-	}, nil, nil)
+	}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3533,7 +3537,7 @@ func TestEIP2718Transition(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -3628,7 +3632,7 @@ func TestEIP1559Transition(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(diskdb)
 
-	chain, err := NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil)
+	chain, err := NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
diff --git a/core/chain_makers_test.go b/core/chain_makers_test.go
index 85a029f7c7..d3024cf90a 100644
--- a/core/chain_makers_test.go
+++ b/core/chain_makers_test.go
@@ -79,7 +79,7 @@ func ExampleGenerateChain() {
 	})
 
 	// Import the chain. This runs all block validation rules.
-	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer blockchain.Stop()
 
 	if i, err := blockchain.InsertChain(chain); err != nil {
diff --git a/core/dao_test.go b/core/dao_test.go
index c9c765a383..b43589ff51 100644
--- a/core/dao_test.go
+++ b/core/dao_test.go
@@ -45,7 +45,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	proConf.DAOForkBlock = forkBlock
 	proConf.DAOForkSupport = true
 
-	proBc, _ := NewBlockChain(proDb, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+	proBc, _ := NewBlockChain(proDb, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer proBc.Stop()
 
 	conDb := rawdb.NewMemoryDatabase()
@@ -55,7 +55,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	conConf.DAOForkBlock = forkBlock
 	conConf.DAOForkSupport = false
 
-	conBc, _ := NewBlockChain(conDb, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+	conBc, _ := NewBlockChain(conDb, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer conBc.Stop()
 
 	if _, err := proBc.InsertChain(prefix); err != nil {
@@ -69,7 +69,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		// Create a pro-fork block, and try to feed into the no-fork chain
 		db = rawdb.NewMemoryDatabase()
 		gspec.MustCommit(db)
-		bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+		bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		defer bc.Stop()
 
 		blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -94,7 +94,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 		// Create a no-fork block, and try to feed into the pro-fork chain
 		db = rawdb.NewMemoryDatabase()
 		gspec.MustCommit(db)
-		bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+		bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		defer bc.Stop()
 
 		blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
@@ -120,7 +120,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Verify that contra-forkers accept pro-fork extra-datas after forking finishes
 	db = rawdb.NewMemoryDatabase()
 	gspec.MustCommit(db)
-	bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+	bc, _ := NewBlockChain(db, nil, &conConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer bc.Stop()
 
 	blocks := conBc.GetBlocksFromHash(conBc.CurrentBlock().Hash(), int(conBc.CurrentBlock().NumberU64()))
@@ -140,7 +140,7 @@ func TestDAOForkRangeExtradata(t *testing.T) {
 	// Verify that pro-forkers accept contra-fork extra-datas after forking finishes
 	db = rawdb.NewMemoryDatabase()
 	gspec.MustCommit(db)
-	bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil)
+	bc, _ = NewBlockChain(db, nil, &proConf, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	defer bc.Stop()
 
 	blocks = proBc.GetBlocksFromHash(proBc.CurrentBlock().Hash(), int(proBc.CurrentBlock().NumberU64()))
diff --git a/core/forkchoice.go b/core/forkchoice.go
index b0dbb200ec..a2ce4cd7d9 100644
--- a/core/forkchoice.go
+++ b/core/forkchoice.go
@@ -22,6 +22,7 @@ import (
 	"math/big"
 	mrand "math/rand"
 
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -54,18 +55,21 @@ type ForkChoice struct {
 	// local td is equal to the extern one. It can be nil for light
 	// client
 	preserve func(header *types.Header) bool
+
+	validator ethereum.ChainValidator
 }
 
-func NewForkChoice(chainReader ChainReader, preserve func(header *types.Header) bool) *ForkChoice {
+func NewForkChoice(chainReader ChainReader, preserve func(header *types.Header) bool, validator ethereum.ChainValidator) *ForkChoice {
 	// Seed a fast but crypto originating random generator
 	seed, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
 	if err != nil {
 		log.Crit("Failed to initialize random seed", "err", err)
 	}
 	return &ForkChoice{
-		chain:    chainReader,
-		rand:     mrand.New(mrand.NewSource(seed.Int64())),
-		preserve: preserve,
+		chain:     chainReader,
+		rand:      mrand.New(mrand.NewSource(seed.Int64())), //nolint:gosec
+		preserve:  preserve,
+		validator: validator,
 	}
 }
 
@@ -106,3 +110,15 @@ func (f *ForkChoice) ReorgNeeded(current *types.Header, header *types.Header) (b
 	}
 	return reorg, nil
 }
+
+// ValidateReorg calls the chain validator service to check if the reorg is valid or not
+func (f *ForkChoice) ValidateReorg(current *types.Header, chain []*types.Header) (bool, error) {
+	// Call the bor chain validator service
+	if f.validator != nil {
+		if isValid := f.validator.IsValidChain(current, chain); !isValid {
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
diff --git a/core/forkchoice_test.go b/core/forkchoice_test.go
new file mode 100644
index 0000000000..2e7b40d8ff
--- /dev/null
+++ b/core/forkchoice_test.go
@@ -0,0 +1,240 @@
+package core
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+// chainValidatorFake is a mock for the chain validator service
+type chainValidatorFake struct {
+	validate func(currentHeader *types.Header, chain []*types.Header) bool
+}
+
+// chainReaderFake is a mock for the chain reader service
+type chainReaderFake struct {
+	getTd func(hash common.Hash, number uint64) *big.Int
+}
+
+func newChainValidatorFake(validate func(currentHeader *types.Header, chain []*types.Header) bool) *chainValidatorFake {
+	return &chainValidatorFake{validate: validate}
+}
+
+func newChainReaderFake(getTd func(hash common.Hash, number uint64) *big.Int) *chainReaderFake {
+	return &chainReaderFake{getTd: getTd}
+}
+
+func TestPastChainInsert(t *testing.T) {
+	t.Parallel()
+
+	var (
+		db      = rawdb.NewMemoryDatabase()
+		genesis = (&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(db)
+	)
+
+	hc, err := NewHeaderChain(db, params.AllEthashProtocolChanges, ethash.NewFaker(), func() bool { return false })
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Create mocks for forker
+	getTd := func(hash common.Hash, number uint64) *big.Int {
+		return big.NewInt(int64(number))
+	}
+	validate := func(currentHeader *types.Header, chain []*types.Header) bool {
+		// Put all explicit conditions here
+		// If canonical chain is empty and we're importing a chain of 64 blocks
+		if currentHeader.Number.Uint64() == uint64(0) && len(chain) == 64 {
+			return true
+		}
+		// If canonical chain is of len 64 and we're importing a past chain from 54-64, then accept it
+		if currentHeader.Number.Uint64() == uint64(64) && chain[0].Number.Uint64() == 55 && len(chain) == 10 {
+			return true
+		}
+
+		return false
+	}
+	mockChainReader := newChainReaderFake(getTd)
+	mockChainValidator := newChainValidatorFake(validate)
+	mockForker := NewForkChoice(mockChainReader, nil, mockChainValidator)
+
+	// chain A: G->A1->A2...A64
+	chainA := makeHeaderChain(genesis.Header(), 64, ethash.NewFaker(), db, 10)
+
+	// Inserting 64 headers on an empty chain
+	// expecting 1 write status with no error
+	testInsert(t, hc, chainA, CanonStatTy, nil, mockForker)
+
+	// The current chain is: G->A1->A2...A64
+	// chain B: G->A1->A2...A44->B45->B46...B64
+	chainB := makeHeaderChain(chainA[43], 20, ethash.NewFaker(), db, 10)
+
+	// The current chain is: G->A1->A2...A64
+	// chain C: G->A1->A2...A54->C55->C56...C64
+	chainC := makeHeaderChain(chainA[53], 10, ethash.NewFaker(), db, 10)
+
+	// Update the function to consider chainC with higher difficulty
+	getTd = func(hash common.Hash, number uint64) *big.Int {
+		td := big.NewInt(int64(number))
+		if hash == chainB[len(chainB)-1].Hash() || hash == chainC[len(chainC)-1].Hash() {
+			td = big.NewInt(65)
+		}
+
+		return td
+	}
+	mockChainReader = newChainReaderFake(getTd)
+	mockForker = NewForkChoice(mockChainReader, nil, mockChainValidator)
+
+	// Inserting 20 blocks from chainC on canonical chain
+	// expecting 2 write status with no error
+	testInsert(t, hc, chainB, SideStatTy, nil, mockForker)
+
+	// Inserting 10 blocks from chainB on canonical chain
+	// expecting 1 write status with no error
+	testInsert(t, hc, chainC, CanonStatTy, nil, mockForker)
+}
+
+func TestFutureChainInsert(t *testing.T) {
+	t.Parallel()
+
+	var (
+		db      = rawdb.NewMemoryDatabase()
+		genesis = (&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(db)
+	)
+
+	hc, err := NewHeaderChain(db, params.AllEthashProtocolChanges, ethash.NewFaker(), func() bool { return false })
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Create mocks for forker
+	getTd := func(hash common.Hash, number uint64) *big.Int {
+		return big.NewInt(int64(number))
+	}
+	validate := func(currentHeader *types.Header, chain []*types.Header) bool {
+		// Put all explicit conditions here
+		// If canonical chain is empty and we're importing a chain of 64 blocks
+		if currentHeader.Number.Uint64() == uint64(0) && len(chain) == 64 {
+			return true
+		}
+		// If length of future chains > some value, they should not be accepted
+		if currentHeader.Number.Uint64() == uint64(64) && len(chain) <= 10 {
+			return true
+		}
+
+		return false
+	}
+	mockChainReader := newChainReaderFake(getTd)
+	mockChainValidator := newChainValidatorFake(validate)
+	mockForker := NewForkChoice(mockChainReader, nil, mockChainValidator)
+
+	// chain A: G->A1->A2...A64
+	chainA := makeHeaderChain(genesis.Header(), 64, ethash.NewFaker(), db, 10)
+
+	// Inserting 64 headers on an empty chain
+	// expecting 1 write status with no error
+	testInsert(t, hc, chainA, CanonStatTy, nil, mockForker)
+
+	// The current chain is: G->A1->A2...A64
+	// chain B: G->A1->A2...A64->B65->B66...B84
+	chainB := makeHeaderChain(chainA[63], 20, ethash.NewFaker(), db, 10)
+
+	// Inserting 20 headers on the canonical chain
+	// expecting 0 write status with no error
+	testInsert(t, hc, chainB, SideStatTy, nil, mockForker)
+
+	// The current chain is: G->A1->A2...A64
+	// chain C: G->A1->A2...A64->C65->C66...C74
+	chainC := makeHeaderChain(chainA[63], 10, ethash.NewFaker(), db, 10)
+
+	// Inserting 10 headers on the canonical chain
+	// expecting 0 write status with no error
+	testInsert(t, hc, chainC, CanonStatTy, nil, mockForker)
+}
+
+func TestOverlappingChainInsert(t *testing.T) {
+	t.Parallel()
+
+	var (
+		db      = rawdb.NewMemoryDatabase()
+		genesis = (&Genesis{BaseFee: big.NewInt(params.InitialBaseFee)}).MustCommit(db)
+	)
+
+	hc, err := NewHeaderChain(db, params.AllEthashProtocolChanges, ethash.NewFaker(), func() bool { return false })
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Create mocks for forker
+	getTd := func(hash common.Hash, number uint64) *big.Int {
+		return big.NewInt(int64(number))
+	}
+	validate := func(currentHeader *types.Header, chain []*types.Header) bool {
+		// Put all explicit conditions here
+		// If canonical chain is empty and we're importing a chain of 64 blocks
+		if currentHeader.Number.Uint64() == uint64(0) && len(chain) == 64 {
+			return true
+		}
+		// If length of chain is > some fixed value then don't accept it
+		if currentHeader.Number.Uint64() == uint64(64) && len(chain) <= 20 {
+			return true
+		}
+
+		return false
+	}
+	mockChainReader := newChainReaderFake(getTd)
+	mockChainValidator := newChainValidatorFake(validate)
+	mockForker := NewForkChoice(mockChainReader, nil, mockChainValidator)
+
+	// chain A: G->A1->A2...A64
+	chainA := makeHeaderChain(genesis.Header(), 64, ethash.NewFaker(), db, 10)
+
+	// Inserting 64 headers on an empty chain
+	// expecting 1 write status with no error
+	testInsert(t, hc, chainA, CanonStatTy, nil, mockForker)
+
+	// The current chain is: G->A1->A2...A64
+	// chain B: G->A1->A2...A54->B55->B56...B84
+	chainB := makeHeaderChain(chainA[53], 30, ethash.NewFaker(), db, 10)
+
+	// Inserting 20 blocks on canonical chain
+	// expecting 2 write status with no error
+	testInsert(t, hc, chainB, SideStatTy, nil, mockForker)
+
+	// The current chain is: G->A1->A2...A64
+	// chain C: G->A1->A2...A54->C55->C56...C74
+	chainC := makeHeaderChain(chainA[53], 20, ethash.NewFaker(), db, 10)
+
+	// Inserting 10 blocks on canonical chain
+	// expecting 1 write status with no error
+	testInsert(t, hc, chainC, CanonStatTy, nil, mockForker)
+}
+
+// Mock chain reader functions
+func (c *chainReaderFake) Config() *params.ChainConfig {
+	return &params.ChainConfig{TerminalTotalDifficulty: nil}
+}
+func (c *chainReaderFake) GetTd(hash common.Hash, number uint64) *big.Int {
+	return c.getTd(hash, number)
+}
+
+// Mock chain validator functions
+func (w *chainValidatorFake) IsValidPeer(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
+	return true, nil
+}
+func (w *chainValidatorFake) IsValidChain(current *types.Header, headers []*types.Header) bool {
+	return w.validate(current, headers)
+}
+func (w *chainValidatorFake) ProcessCheckpoint(endBlockNum uint64, endBlockHash common.Hash) {}
+func (w *chainValidatorFake) GetCheckpointWhitelist() map[uint64]common.Hash {
+	return nil
+}
+func (w *chainValidatorFake) PurgeCheckpointWhitelist() {}
+func (w *chainValidatorFake) GetCheckpoints(current, sidechainHeader *types.Header, sidechainCheckpoints []*types.Header) (map[uint64]*types.Header, error) {
+	return map[uint64]*types.Header{}, nil
+}
diff --git a/core/genesis_test.go b/core/genesis_test.go
index e8010e3d4e..3d3480bff8 100644
--- a/core/genesis_test.go
+++ b/core/genesis_test.go
@@ -117,7 +117,7 @@ func TestSetupGenesis(t *testing.T) {
 				// Advance to block #4, past the homestead transition block of customg.
 				genesis := oldcustomg.MustCommit(db)
 
-				bc, _ := NewBlockChain(db, nil, oldcustomg.Config, ethash.NewFullFaker(), vm.Config{}, nil, nil)
+				bc, _ := NewBlockChain(db, nil, oldcustomg.Config, ethash.NewFullFaker(), vm.Config{}, nil, nil, nil)
 				defer bc.Stop()
 
 				blocks, _ := GenerateChain(oldcustomg.Config, genesis, ethash.NewFaker(), db, 4, nil)
diff --git a/core/headerchain.go b/core/headerchain.go
index 99364f638f..83e1125305 100644
--- a/core/headerchain.go
+++ b/core/headerchain.go
@@ -283,8 +283,10 @@ func (hc *HeaderChain) writeHeadersAndSetHead(headers []*types.Header, forker *F
 			lastHeader: lastHeader,
 		}
 	)
+
 	// Ask the fork choicer if the reorg is necessary
-	if reorg, err := forker.ReorgNeeded(hc.CurrentHeader(), lastHeader); err != nil {
+	reorg, err := forker.ReorgNeeded(hc.CurrentHeader(), lastHeader)
+	if err != nil {
 		return nil, err
 	} else if !reorg {
 		if inserted != 0 {
@@ -292,6 +294,16 @@ func (hc *HeaderChain) writeHeadersAndSetHead(headers []*types.Header, forker *F
 		}
 		return result, nil
 	}
+
+	isValid, err := forker.ValidateReorg(hc.CurrentHeader(), headers)
+	if err != nil {
+		return nil, err
+	} else if !isValid {
+		if inserted != 0 {
+			result.status = SideStatTy
+		}
+		return result, nil
+	}
 	// Special case, all the inserted headers are already on the canonical
 	// header chain, skip the reorg operation.
 	if hc.GetCanonicalHash(lastHeader.Number.Uint64()) == lastHash && lastHeader.Number.Uint64() <= hc.CurrentHeader().Number.Uint64() {
diff --git a/core/headerchain_test.go b/core/headerchain_test.go
index ed0522671f..85432876fa 100644
--- a/core/headerchain_test.go
+++ b/core/headerchain_test.go
@@ -84,7 +84,7 @@ func TestHeaderInsertion(t *testing.T) {
 	chainB := makeHeaderChain(chainA[0], 128, ethash.NewFaker(), db, 10)
 	log.Root().SetHandler(log.StdoutHandler)
 
-	forker := NewForkChoice(hc, nil)
+	forker := NewForkChoice(hc, nil, nil)
 	// Inserting 64 headers on an empty chain, expecting
 	// 1 callbacks, 1 canon-status, 0 sidestatus,
 	testInsert(t, hc, chainA[:64], CanonStatTy, nil, forker)
diff --git a/core/rawdb/bor_receipt.go b/core/rawdb/bor_receipt.go
index 63c4be12a1..e225083741 100644
--- a/core/rawdb/bor_receipt.go
+++ b/core/rawdb/bor_receipt.go
@@ -18,7 +18,11 @@ var (
 	getDerivedBorTxHash = types.GetDerivedBorTxHash
 
 	// borTxLookupPrefix + hash -> transaction/receipt lookup metadata
-	borTxLookupPrefix = []byte("matic-bor-tx-lookup-")
+	borTxLookupPrefix = []byte(borTxLookupPrefixStr)
+)
+
+const (
+	borTxLookupPrefixStr = "matic-bor-tx-lookup-"
 
 	// freezerBorReceiptTable indicates the name of the freezer bor receipts table.
 	freezerBorReceiptTable = "matic-bor-receipts"
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 1d31cf470b..c236a79b5a 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -601,8 +601,8 @@ func (s *StateDB) createObject(addr common.Address) (newobj, prev *stateObject)
 // CreateAccount is called during the EVM CREATE operation. The situation might arise that
 // a contract does the following:
 //
-//   1. sends funds to sha(account ++ (nonce + 1))
-//   2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1)
+//  1. sends funds to sha(account ++ (nonce + 1))
+//  2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1)
 //
 // Carrying over the balance ensures that Ether doesn't disappear.
 func (s *StateDB) CreateAccount(addr common.Address) {
diff --git a/core/state_processor_test.go b/core/state_processor_test.go
index 158e8c1eeb..5dc076a11c 100644
--- a/core/state_processor_test.go
+++ b/core/state_processor_test.go
@@ -94,7 +94,7 @@ func TestStateProcessorErrors(t *testing.T) {
 				},
 			}
 			genesis       = gspec.MustCommit(db)
-			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		)
 		defer blockchain.Stop()
 		bigNumber := new(big.Int).SetBytes(common.FromHex("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"))
@@ -235,7 +235,7 @@ func TestStateProcessorErrors(t *testing.T) {
 				},
 			}
 			genesis       = gspec.MustCommit(db)
-			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		)
 		defer blockchain.Stop()
 		for i, tt := range []struct {
@@ -275,7 +275,7 @@ func TestStateProcessorErrors(t *testing.T) {
 				},
 			}
 			genesis       = gspec.MustCommit(db)
-			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+			blockchain, _ = NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		)
 		defer blockchain.Stop()
 		for i, tt := range []struct {
diff --git a/core/tests/blockchain_repair_test.go b/core/tests/blockchain_repair_test.go
index 15ab67dd1c..d99978a134 100644
--- a/core/tests/blockchain_repair_test.go
+++ b/core/tests/blockchain_repair_test.go
@@ -1891,7 +1891,7 @@ func testRepair(t *testing.T, tt *rewindTest, snapshots bool) {
 
 	defer db.Close()
 
-	newChain, err := core.NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	newChain, err := core.NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -1969,7 +1969,7 @@ func TestIssue23496(t *testing.T) {
 		}
 	)
 
-	chain, err := core.NewBlockChain(db, config, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(db, config, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create chain: %v", err)
 	}
@@ -2024,7 +2024,7 @@ func TestIssue23496(t *testing.T) {
 
 	defer db.Close()
 
-	chain, err = core.NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, err = core.NewBlockChain(db, nil, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
diff --git a/core/tests/blockchain_sethead_test.go b/core/tests/blockchain_sethead_test.go
index 3a2d87c4eb..ad6e78697d 100644
--- a/core/tests/blockchain_sethead_test.go
+++ b/core/tests/blockchain_sethead_test.go
@@ -1987,7 +1987,7 @@ func testSetHead(t *testing.T, tt *rewindTest, snapshots bool) {
 		config.SnapshotWait = true
 	}
 
-	chain, err := core.NewBlockChain(db, config, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(db, config, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create chain: %v", err)
 	}
diff --git a/core/tests/blockchain_snapshot_test.go b/core/tests/blockchain_snapshot_test.go
index fb4c09867c..26ef58f99f 100644
--- a/core/tests/blockchain_snapshot_test.go
+++ b/core/tests/blockchain_snapshot_test.go
@@ -84,7 +84,7 @@ func (basic *snapshotTestBasic) prepare(t *testing.T) (*core.BlockChain, []*type
 		cacheConfig = core.DefaultCacheConfig
 	)
 
-	chain, err := core.NewBlockChain(db, cacheConfig, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(db, cacheConfig, params.AllEthashProtocolChanges, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create chain: %v", err)
 	}
@@ -246,7 +246,7 @@ func (snaptest *snapshotTest) test(t *testing.T) {
 	// Restart the chain normally
 	chain.Stop()
 
-	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -283,13 +283,13 @@ func (snaptest *crashSnapshotTest) test(t *testing.T) {
 	// the crash, we do restart twice here: one after the crash and one
 	// after the normal stop. It's used to ensure the broken snapshot
 	// can be detected all the time.
-	newchain, err := core.NewBlockChain(newdb, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(newdb, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
 	newchain.Stop()
 
-	newchain, err = core.NewBlockChain(newdb, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err = core.NewBlockChain(newdb, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -327,7 +327,7 @@ func (snaptest *gappedSnapshotTest) test(t *testing.T) {
 		SnapshotLimit:  0,
 	}
 
-	newchain, err := core.NewBlockChain(snaptest.db, cacheConfig, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(snaptest.db, cacheConfig, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -336,7 +336,7 @@ func (snaptest *gappedSnapshotTest) test(t *testing.T) {
 	newchain.Stop()
 
 	// Restart the chain with enabling the snapshot
-	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -365,7 +365,7 @@ func (snaptest *setHeadSnapshotTest) test(t *testing.T) {
 	chain.SetHead(snaptest.setHead)
 	chain.Stop()
 
-	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -396,7 +396,7 @@ func (snaptest *restartCrashSnapshotTest) test(t *testing.T) {
 	// and state committed.
 	chain.Stop()
 
-	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -414,7 +414,7 @@ func (snaptest *restartCrashSnapshotTest) test(t *testing.T) {
 	// journal and latest state will be committed
 
 	// Restart the chain after the crash
-	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -449,8 +449,7 @@ func (snaptest *wipeCrashSnapshotTest) test(t *testing.T) {
 		TrieTimeLimit:  5 * time.Minute,
 		SnapshotLimit:  0,
 	}
-
-	newchain, err := core.NewBlockChain(snaptest.db, config, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err := core.NewBlockChain(snaptest.db, config, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
@@ -467,14 +466,13 @@ func (snaptest *wipeCrashSnapshotTest) test(t *testing.T) {
 		SnapshotLimit:  256,
 		SnapshotWait:   false, // Don't wait rebuild
 	}
-
-	_, err = core.NewBlockChain(snaptest.db, config, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	_, err = core.NewBlockChain(snaptest.db, config, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
 	// Simulate the blockchain crash.
 
-	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil)
+	newchain, err = core.NewBlockChain(snaptest.db, nil, params.AllEthashProtocolChanges, snaptest.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to recreate chain: %v", err)
 	}
diff --git a/docs/cli/server.md b/docs/cli/server.md
index 0803208e3a..ac43555275 100644
--- a/docs/cli/server.md
+++ b/docs/cli/server.md
@@ -6,7 +6,7 @@ The ```bor server``` command runs the Bor client.
 
 - ```chain```: Name of the chain to sync
 
-- ```name```: Name/Identity of the node
+- ```identity```: Name/Identity of the node
 
 - ```log-level```: Set log level for the server
 
@@ -22,7 +22,7 @@ The ```bor server``` command runs the Bor client.
 
 - ```requiredblocks```: Comma separated block number-to-hash mappings to enforce (<number>=<hash>)
 
-- ```no-snapshot```: Disables the snapshot-database mode (default = false)
+- ```snapshot```: Disables/Enables the snapshot-database mode (default = true)
 
 - ```bor.heimdall```: URL of Heimdall service
 
@@ -88,9 +88,17 @@ The ```bor server``` command runs the Bor client.
 
 - ```ipcpath```: Filename for IPC socket/pipe within the datadir (explicit paths escape it)
 
-- ```jsonrpc.corsdomain```: Comma separated list of domains from which to accept cross origin requests (browser enforced)
+- ```http.corsdomain```: Comma separated list of domains from which to accept cross origin requests (browser enforced)
 
-- ```jsonrpc.vhosts```: Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.
+- ```http.vhosts```: Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.
+
+- ```ws.corsdomain```: Comma separated list of domains from which to accept cross origin requests (browser enforced)
+
+- ```ws.vhosts```: Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.
+
+- ```graphql.corsdomain```: Comma separated list of domains from which to accept cross origin requests (browser enforced)
+
+- ```graphql.vhosts```: Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.
 
 - ```http```: Enable the HTTP-RPC server
 
@@ -100,7 +108,7 @@ The ```bor server``` command runs the Bor client.
 
 - ```http.rpcprefix```: HTTP path path prefix on which JSON-RPC is served. Use '/' to serve on all paths.
 
-- ```http.modules```: API's offered over the HTTP-RPC interface
+- ```http.api```: API's offered over the HTTP-RPC interface
 
 - ```ws```: Enable the WS-RPC server
 
@@ -110,7 +118,7 @@ The ```bor server``` command runs the Bor client.
 
 - ```ws.rpcprefix```: HTTP path prefix on which JSON-RPC is served. Use '/' to serve on all paths.
 
-- ```ws.modules```: API's offered over the WS-RPC interface
+- ```ws.api```: API's offered over the WS-RPC interface
 
 - ```graphql```: Enable GraphQL on the HTTP-RPC server. Note that GraphQL can only be started if an HTTP server is started as well.
 
diff --git a/eth/backend.go b/eth/backend.go
index e3376056a2..8f2ae1ea2c 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -41,6 +41,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/eth/downloader"
+	"github.com/ethereum/go-ethereum/eth/downloader/whitelist"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
 	"github.com/ethereum/go-ethereum/eth/filters"
 	"github.com/ethereum/go-ethereum/eth/gasprice"
@@ -219,7 +220,10 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 			Preimages:           config.Preimages,
 		}
 	)
-	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, chainConfig, eth.engine, vmConfig, eth.shouldPreserve, &config.TxLookupLimit)
+
+	checker := whitelist.NewService(10)
+
+	eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, chainConfig, eth.engine, vmConfig, eth.shouldPreserve, &config.TxLookupLimit, checker)
 	if err != nil {
 		return nil, err
 	}
@@ -260,6 +264,7 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 		Checkpoint:         checkpoint,
 		EthAPI:             ethAPI,
 		PeerRequiredBlocks: config.PeerRequiredBlocks,
+		checker:            checker,
 	}); err != nil {
 		return nil, err
 	}
@@ -622,6 +627,13 @@ func (s *Ethereum) Start() error {
 	return nil
 }
 
+var (
+	ErrNotBorConsensus             = errors.New("not bor consensus was given")
+	ErrBorConsensusWithoutHeimdall = errors.New("bor consensus without heimdall")
+
+	whitelistTimeout = 30 * time.Second
+)
+
 // StartCheckpointWhitelistService starts the goroutine to fetch checkpoints and update the
 // checkpoint whitelist map.
 func (s *Ethereum) startCheckpointWhitelistService() {
@@ -633,8 +645,11 @@ func (s *Ethereum) startCheckpointWhitelistService() {
 	}
 
 	// first run the checkpoint whitelist
-	// TODO: add context timeout if needed
-	err := s.handleWhitelistCheckpoint(context.Background())
+	firstCtx, cancel := context.WithTimeout(context.Background(), whitelistTimeout)
+	err := s.handleWhitelistCheckpoint(firstCtx, true)
+
+	cancel()
+
 	if err != nil {
 		if errors.Is(err, ErrBorConsensusWithoutHeimdall) || errors.Is(err, ErrNotBorConsensus) {
 			return
@@ -649,8 +664,11 @@ func (s *Ethereum) startCheckpointWhitelistService() {
 	for {
 		select {
 		case <-ticker.C:
-			// TODO: add context timeout if needed
-			err = s.handleWhitelistCheckpoint(context.Background())
+			ctx, cancel := context.WithTimeout(context.Background(), whitelistTimeout)
+			err := s.handleWhitelistCheckpoint(ctx, false)
+
+			cancel()
+
 			if err != nil {
 				log.Warn("unable to whitelist checkpoint", "err", err)
 			}
@@ -660,13 +678,8 @@ func (s *Ethereum) startCheckpointWhitelistService() {
 	}
 }
 
-var (
-	ErrNotBorConsensus             = errors.New("not bor consensus was given")
-	ErrBorConsensusWithoutHeimdall = errors.New("bor consensus without heimdall")
-)
-
 // handleWhitelistCheckpoint handles the checkpoint whitelist mechanism.
-func (s *Ethereum) handleWhitelistCheckpoint(ctx context.Context) error {
+func (s *Ethereum) handleWhitelistCheckpoint(ctx context.Context, first bool) error {
 	ethHandler := (*ethHandler)(s.handler)
 
 	bor, ok := ethHandler.chain.Engine().(*bor.Bor)
@@ -678,13 +691,18 @@ func (s *Ethereum) handleWhitelistCheckpoint(ctx context.Context) error {
 		return ErrBorConsensusWithoutHeimdall
 	}
 
-	endBlockNum, endBlockHash, err := ethHandler.fetchWhitelistCheckpoint(ctx, bor)
-	if err != nil {
+	blockNums, blockHashes, err := ethHandler.fetchWhitelistCheckpoints(ctx, bor, first)
+	// If the array is empty, we're bound to receive an error. Non-nill error and non-empty array
+	// means that array has partial elements and it failed for some block. We'll add those partial
+	// elements anyway.
+	if len(blockNums) == 0 {
 		return err
 	}
 
 	// Update the checkpoint whitelist map.
-	ethHandler.downloader.ProcessCheckpoint(endBlockNum, endBlockHash)
+	for i := 0; i < len(blockNums); i++ {
+		ethHandler.downloader.ProcessCheckpoint(blockNums[i], blockHashes[i])
+	}
 
 	return nil
 }
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 1a9d815ccd..34b8c95715 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -144,7 +144,7 @@ type Downloader struct {
 	quitCh   chan struct{} // Quit channel to signal termination
 	quitLock sync.Mutex    // Lock to prevent double closes
 
-	ChainValidator
+	ethereum.ChainValidator
 
 	// Testing hooks
 	syncInitHook     func(uint64, uint64)  // Method to call upon initiating a new sync run
@@ -153,14 +153,6 @@ type Downloader struct {
 	chainInsertHook  func([]*fetchResult)  // Method to call upon inserting a chain of blocks (possibly in multiple invocations)
 }
 
-// interface for whitelist service
-type ChainValidator interface {
-	IsValidChain(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error)
-	ProcessCheckpoint(endBlockNum uint64, endBlockHash common.Hash)
-	GetCheckpointWhitelist() map[uint64]common.Hash
-	PurgeCheckpointWhitelist()
-}
-
 // LightChain encapsulates functions required to synchronise a light chain.
 type LightChain interface {
 	// HasHeader verifies a header's presence in the local chain.
@@ -216,7 +208,7 @@ type BlockChain interface {
 
 // New creates a new downloader to fetch hashes and blocks from remote peers.
 //nolint: staticcheck
-func New(checkpoint uint64, stateDb ethdb.Database, mux *event.TypeMux, chain BlockChain, lightchain LightChain, dropPeer peerDropFn, success func(), whitelistService ChainValidator) *Downloader {
+func New(checkpoint uint64, stateDb ethdb.Database, mux *event.TypeMux, chain BlockChain, lightchain LightChain, dropPeer peerDropFn, success func(), whitelistService ethereum.ChainValidator) *Downloader {
 	if lightchain == nil {
 		lightchain = chain
 	}
@@ -799,9 +791,11 @@ func (d *Downloader) getFetchHeadersByNumber(p *peerConnection) func(number uint
 // In the rare scenario when we ended up on a long reorganisation (i.e. none of
 // the head links match), we do a binary search to find the common ancestor.
 func (d *Downloader) findAncestor(p *peerConnection, remoteHeader *types.Header) (uint64, error) {
-	// Check the validity of chain to be downloaded
-	if _, err := d.IsValidChain(remoteHeader, d.getFetchHeadersByNumber(p)); err != nil {
-		return 0, err
+	// Check the validity of peer from which the chain is to be downloaded
+	if d.ChainValidator != nil {
+		if _, err := d.IsValidPeer(remoteHeader, d.getFetchHeadersByNumber(p)); err != nil {
+			return 0, err
+		}
 	}
 
 	// Figure out the valid ancestor range to prevent rewrite attacks
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 37b07424dd..d8765ef077 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -71,7 +71,7 @@ func newTester() *downloadTester {
 
 	core.GenesisBlockForTesting(db, testAddress, big.NewInt(1000000000000000))
 
-	chain, err := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if err != nil {
 		panic(err)
 	}
@@ -88,7 +88,7 @@ func newTester() *downloadTester {
 	return tester
 }
 
-func (dl *downloadTester) setWhitelist(w ChainValidator) {
+func (dl *downloadTester) setWhitelist(w ethereum.ChainValidator) {
 	dl.downloader.ChainValidator = w
 }
 
@@ -1416,9 +1416,9 @@ func newWhitelistFake(validate func(count int) (bool, error)) *whitelistFake {
 	return &whitelistFake{0, validate}
 }
 
-// IsValidChain is the mock function which the downloader will use to validate the chain
+// IsValidPeer is the mock function which the downloader will use to validate the chain
 // to be received from a peer.
-func (w *whitelistFake) IsValidChain(_ *types.Header, _ func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
+func (w *whitelistFake) IsValidPeer(_ *types.Header, _ func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
 	defer func() {
 		w.count++
 	}()
@@ -1426,13 +1426,18 @@ func (w *whitelistFake) IsValidChain(_ *types.Header, _ func(number uint64, amou
 	return w.validate(w.count)
 }
 
+func (w *whitelistFake) IsValidChain(current *types.Header, headers []*types.Header) bool {
+	return true
+}
 func (w *whitelistFake) ProcessCheckpoint(_ uint64, _ common.Hash) {}
 
 func (w *whitelistFake) GetCheckpointWhitelist() map[uint64]common.Hash {
 	return nil
 }
-
 func (w *whitelistFake) PurgeCheckpointWhitelist() {}
+func (w *whitelistFake) GetCheckpoints(current, sidechainHeader *types.Header, sidechainCheckpoints []*types.Header) (map[uint64]*types.Header, error) {
+	return map[uint64]*types.Header{}, nil
+}
 
 // TestFakedSyncProgress66WhitelistMismatch tests if in case of whitelisted
 // checkpoint mismatch with opposite peer, the sync should fail.
diff --git a/eth/downloader/testchain_test.go b/eth/downloader/testchain_test.go
index 8b873343ca..cd4d9e6550 100644
--- a/eth/downloader/testchain_test.go
+++ b/eth/downloader/testchain_test.go
@@ -214,7 +214,7 @@ func newTestBlockchain(blocks []*types.Block) *core.BlockChain {
 		db := rawdb.NewMemoryDatabase()
 		core.GenesisBlockForTesting(db, testAddress, big.NewInt(1000000000000000))
 
-		chain, err := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+		chain, err := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 		if err != nil {
 			panic(err)
 		}
diff --git a/eth/downloader/whitelist/service.go b/eth/downloader/whitelist/service.go
index 7036f24a8f..0e905cce28 100644
--- a/eth/downloader/whitelist/service.go
+++ b/eth/downloader/whitelist/service.go
@@ -15,7 +15,8 @@ type Service struct {
 	m                   sync.Mutex
 	checkpointWhitelist map[uint64]common.Hash // Checkpoint whitelist, populated by reaching out to heimdall
 	checkpointOrder     []uint64               // Checkpoint order, populated by reaching out to heimdall
-	maxCapacity         uint
+	maxCapacity         uint                   // Max capacity of the whitelist
+	checkpointInterval  uint64                 // Checkpoint interval, until which we can allow importing
 }
 
 func NewService(maxCapacity uint) *Service {
@@ -23,6 +24,7 @@ func NewService(maxCapacity uint) *Service {
 		checkpointWhitelist: make(map[uint64]common.Hash),
 		checkpointOrder:     []uint64{},
 		maxCapacity:         maxCapacity,
+		checkpointInterval:  256, // TODO: make it configurable through params?
 	}
 }
 
@@ -31,9 +33,9 @@ var (
 	ErrNoRemoteCheckoint  = errors.New("remote peer doesn't have a checkoint")
 )
 
-// IsValidChain checks if the chain we're about to receive from this peer is valid or not
+// IsValidPeer checks if the chain we're about to receive from a peer is valid or not
 // in terms of reorgs. We won't reorg beyond the last bor checkpoint submitted to mainchain.
-func (w *Service) IsValidChain(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
+func (w *Service) IsValidPeer(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error) {
 	// We want to validate the chain by comparing the last checkpointed block
 	// we're storing in `checkpointWhitelist` with the peer's block.
 	//
@@ -70,6 +72,84 @@ func (w *Service) IsValidChain(remoteHeader *types.Header, fetchHeadersByNumber
 	return false, ErrCheckpointMismatch
 }
 
+// IsValidChain checks the validity of chain by comparing it
+// against the local checkpoint entries
+func (w *Service) IsValidChain(currentHeader *types.Header, chain []*types.Header) bool {
+	// Check if we have checkpoints to validate incoming chain in memory
+	if len(w.checkpointWhitelist) == 0 {
+		// We don't have any entries, no additional validation will be possible
+		return true
+	}
+
+	// Return if we've received empty chain
+	if len(chain) == 0 {
+		return false
+	}
+
+	var (
+		oldestCheckpointNumber uint64 = w.checkpointOrder[0]
+		current                uint64 = currentHeader.Number.Uint64()
+	)
+
+	// Check if we have whitelist entries in required range
+	if chain[len(chain)-1].Number.Uint64() < oldestCheckpointNumber {
+		// We have future whitelisted entries, so no additional validation will be possible
+		// This case will occur when bor is in middle of sync, but heimdall is ahead/fully synced.
+		return true
+	}
+
+	// Split the chain into past and future chain
+	pastChain, futureChain := splitChain(current, chain)
+
+	// Add an offset to future chain if it's not in continuity
+	offset := 0
+	if len(futureChain) != 0 {
+		offset += int(futureChain[0].Number.Uint64()-currentHeader.Number.Uint64()) - 1
+	}
+
+	// Don't accept future chain of unacceptable length (from current block)
+	if len(futureChain)+offset > int(w.checkpointInterval) {
+		return false
+	}
+
+	// Iterate over the chain and validate against the last checkpoint
+	// It will handle all cases where the incoming chain has atleast one checkpoint
+	for i := len(pastChain) - 1; i >= 0; i-- {
+		if _, ok := w.checkpointWhitelist[pastChain[i].Number.Uint64()]; ok {
+			return pastChain[i].Hash() == w.checkpointWhitelist[pastChain[i].Number.Uint64()]
+		}
+	}
+
+	return true
+}
+
+func splitChain(current uint64, chain []*types.Header) ([]*types.Header, []*types.Header) {
+	var (
+		pastChain   []*types.Header
+		futureChain []*types.Header
+		first       uint64 = chain[0].Number.Uint64()
+		last        uint64 = chain[len(chain)-1].Number.Uint64()
+	)
+
+	if current >= first {
+		if len(chain) == 1 || current >= last {
+			pastChain = chain
+		} else {
+			pastChain = chain[:current-first+1]
+		}
+	}
+
+	if current < last {
+		if len(chain) == 1 || current < first {
+			futureChain = chain
+		} else {
+			futureChain = chain[current-first+1:]
+		}
+	}
+
+	return pastChain, futureChain
+}
+
 func (w *Service) ProcessCheckpoint(endBlockNum uint64, endBlockHash common.Hash) {
 	w.m.Lock()
 	defer w.m.Unlock()
@@ -116,7 +196,7 @@ func (w *Service) dequeueCheckpointWhitelist() {
 		log.Debug("Dequeing checkpoint whitelist", "block number", w.checkpointOrder[0], "block hash", w.checkpointWhitelist[w.checkpointOrder[0]])
 
 		delete(w.checkpointWhitelist, w.checkpointOrder[0])
-		w.checkpointOrder = w.checkpointOrder[1:]
+		w.checkpointOrder = w.checkpointOrder[1:] // fixme: this slice is growing infinitely and never will be released. also a panic is possible if the last element is going to be removed
 	}
 }
 
diff --git a/eth/downloader/whitelist/service_test.go b/eth/downloader/whitelist/service_test.go
index ca202cc3ad..c21490d125 100644
--- a/eth/downloader/whitelist/service_test.go
+++ b/eth/downloader/whitelist/service_test.go
@@ -2,21 +2,26 @@ package whitelist
 
 import (
 	"errors"
+	"fmt"
 	"math/big"
+	"reflect"
+	"sort"
 	"testing"
+	"time"
 
-	"gotest.tools/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
 // NewMockService creates a new mock whitelist service
-func NewMockService(maxCapacity uint) *Service {
+func NewMockService(maxCapacity uint, checkpointInterval uint64) *Service {
 	return &Service{
 		checkpointWhitelist: make(map[uint64]common.Hash),
 		checkpointOrder:     []uint64{},
 		maxCapacity:         maxCapacity,
+		checkpointInterval:  checkpointInterval,
 	}
 }
 
@@ -24,34 +29,34 @@ func NewMockService(maxCapacity uint) *Service {
 func TestWhitelistCheckpoint(t *testing.T) {
 	t.Parallel()
 
-	s := NewMockService(10)
+	s := NewMockService(10, 10)
 	for i := 0; i < 10; i++ {
 		s.enqueueCheckpointWhitelist(uint64(i), common.Hash{})
 	}
-	assert.Equal(t, s.length(), 10, "expected 10 items in whitelist")
+	require.Equal(t, s.length(), 10, "expected 10 items in whitelist")
 
 	s.enqueueCheckpointWhitelist(11, common.Hash{})
 	s.dequeueCheckpointWhitelist()
-	assert.Equal(t, s.length(), 10, "expected 10 items in whitelist")
+	require.Equal(t, s.length(), 10, "expected 10 items in whitelist")
 }
 
-// TestIsValidChain checks che IsValidChain function in isolation
+// TestIsValidPeer checks the IsValidPeer function in isolation
 // for different cases by providing a mock fetchHeadersByNumber function
-func TestIsValidChain(t *testing.T) {
+func TestIsValidPeer(t *testing.T) {
 	t.Parallel()
 
-	s := NewMockService(10)
+	s := NewMockService(10, 10)
 
 	// case1: no checkpoint whitelist, should consider the chain as valid
-	res, err := s.IsValidChain(nil, nil)
-	assert.NilError(t, err, "expected no error")
-	assert.Equal(t, res, true, "expected chain to be valid")
+	res, err := s.IsValidPeer(nil, nil)
+	require.NoError(t, err, "expected no error")
+	require.Equal(t, res, true, "expected chain to be valid")
 
 	// add checkpoint entries and mock fetchHeadersByNumber function
 	s.ProcessCheckpoint(uint64(0), common.Hash{})
 	s.ProcessCheckpoint(uint64(1), common.Hash{})
 
-	assert.Equal(t, s.length(), 2, "expected 2 items in whitelist")
+	require.Equal(t, s.length(), 2, "expected 2 items in whitelist")
 
 	// create a false function, returning absolutely nothing
 	falseFetchHeadersByNumber := func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error) {
@@ -60,7 +65,7 @@ func TestIsValidChain(t *testing.T) {
 
 	// case2: false fetchHeadersByNumber function provided, should consider the chain as invalid
 	// and throw `ErrNoRemoteCheckoint` error
-	res, err = s.IsValidChain(nil, falseFetchHeadersByNumber)
+	res, err = s.IsValidPeer(nil, falseFetchHeadersByNumber)
 	if err == nil {
 		t.Fatal("expected error, got nil")
 	}
@@ -69,7 +74,7 @@ func TestIsValidChain(t *testing.T) {
 		t.Fatalf("expected error ErrNoRemoteCheckoint, got %v", err)
 	}
 
-	assert.Equal(t, res, false, "expected chain to be invalid")
+	require.Equal(t, res, false, "expected chain to be invalid")
 
 	// case3: correct fetchHeadersByNumber function provided, should consider the chain as valid
 	// create a mock function, returning a the required header
@@ -91,17 +96,316 @@ func TestIsValidChain(t *testing.T) {
 		}
 	}
 
-	res, err = s.IsValidChain(nil, fetchHeadersByNumber)
-	assert.NilError(t, err, "expected no error")
-	assert.Equal(t, res, true, "expected chain to be valid")
+	res, err = s.IsValidPeer(nil, fetchHeadersByNumber)
+	require.NoError(t, err, "expected no error")
+	require.Equal(t, res, true, "expected chain to be valid")
 
 	// add one more checkpoint whitelist entry
 	s.ProcessCheckpoint(uint64(2), common.Hash{})
-	assert.Equal(t, s.length(), 3, "expected 3 items in whitelist")
+	require.Equal(t, s.length(), 3, "expected 3 items in whitelist")
 
 	// case4: correct fetchHeadersByNumber function provided with wrong header
 	// for block number 2. Should consider the chain as invalid and throw an error
-	res, err = s.IsValidChain(nil, fetchHeadersByNumber)
-	assert.Equal(t, err, ErrCheckpointMismatch, "expected checkpoint mismatch error")
-	assert.Equal(t, res, false, "expected chain to be invalid")
+	res, err = s.IsValidPeer(nil, fetchHeadersByNumber)
+	require.Equal(t, err, ErrCheckpointMismatch, "expected checkpoint mismatch error")
+	require.Equal(t, res, false, "expected chain to be invalid")
+}
+
+// TestIsValidChain checks the IsValidChain function in isolation
+// for different cases by providing a mock current header and chain
+func TestIsValidChain(t *testing.T) {
+	t.Parallel()
+
+	s := NewMockService(10, 10)
+	chainA := createMockChain(1, 20) // A1->A2...A19->A20
+	// case1: no checkpoint whitelist, should consider the chain as valid
+	res := s.IsValidChain(nil, chainA)
+	require.Equal(t, res, true, "expected chain to be valid")
+
+	tempChain := createMockChain(21, 22) // A21->A22
+
+	// add mock checkpoint entries
+	s.ProcessCheckpoint(tempChain[0].Number.Uint64(), tempChain[0].Hash())
+	s.ProcessCheckpoint(tempChain[1].Number.Uint64(), tempChain[1].Hash())
+
+	require.Equal(t, s.length(), 2, "expected 2 items in whitelist")
+
+	// case2: We're behind the oldest whitelisted block entry, should consider
+	// the chain as valid as we're still far behind the latest blocks
+	res = s.IsValidChain(chainA[len(chainA)-1], chainA)
+	require.Equal(t, res, true, "expected chain to be valid")
+
+	// Clear checkpoint whitelist and add blocks A5 and A15 in whitelist
+	s.PurgeCheckpointWhitelist()
+	s.ProcessCheckpoint(chainA[5].Number.Uint64(), chainA[5].Hash())
+	s.ProcessCheckpoint(chainA[15].Number.Uint64(), chainA[15].Hash())
+
+	require.Equal(t, s.length(), 2, "expected 2 items in whitelist")
+
+	// case3: Try importing a past chain having valid checkpoint, should
+	// consider the chain as valid
+	res = s.IsValidChain(chainA[len(chainA)-1], chainA)
+	require.Equal(t, res, true, "expected chain to be valid")
+
+	// Clear checkpoint whitelist and mock blocks in whitelist
+	tempChain = createMockChain(20, 20) // A20
+
+	s.PurgeCheckpointWhitelist()
+	s.ProcessCheckpoint(tempChain[0].Number.Uint64(), tempChain[0].Hash())
+
+	require.Equal(t, s.length(), 1, "expected 1 items in whitelist")
+
+	// case4: Try importing a past chain having invalid checkpoint
+	res = s.IsValidChain(chainA[len(chainA)-1], chainA)
+	require.Equal(t, res, false, "expected chain to be invalid")
+
+	// create a future chain to be imported of length <= `checkpointInterval`
+	chainB := createMockChain(21, 30) // B21->B22...B29->B30
+
+	// case5: Try importing a future chain of acceptable length
+	res = s.IsValidChain(chainA[len(chainA)-1], chainB)
+	require.Equal(t, res, true, "expected chain to be valid")
+
+	// create a future chain to be imported of length > `checkpointInterval`
+	chainB = createMockChain(21, 40) // C21->C22...C39->C40
+
+	// case5: Try importing a future chain of unacceptable length
+	res = s.IsValidChain(chainA[len(chainA)-1], chainB)
+	require.Equal(t, res, false, "expected chain to be invalid")
+}
+
+func TestSplitChain(t *testing.T) {
+	t.Parallel()
+
+	type Result struct {
+		pastStart    uint64
+		pastEnd      uint64
+		futureStart  uint64
+		futureEnd    uint64
+		pastLength   int
+		futureLength int
+	}
+
+	// Current chain is at block: X
+	// Incoming chain is represented as [N, M]
+	testCases := []struct {
+		name    string
+		current uint64
+		chain   []*types.Header
+		result  Result
+	}{
+		{name: "X = 10, N = 11, M = 20", current: uint64(10), chain: createMockChain(11, 20), result: Result{futureStart: 11, futureEnd: 20, futureLength: 10}},
+		{name: "X = 10, N = 13, M = 20", current: uint64(10), chain: createMockChain(13, 20), result: Result{futureStart: 13, futureEnd: 20, futureLength: 8}},
+		{name: "X = 10, N = 2, M = 10", current: uint64(10), chain: createMockChain(2, 10), result: Result{pastStart: 2, pastEnd: 10, pastLength: 9}},
+		{name: "X = 10, N = 2, M = 9", current: uint64(10), chain: createMockChain(2, 9), result: Result{pastStart: 2, pastEnd: 9, pastLength: 8}},
+		{name: "X = 10, N = 2, M = 8", current: uint64(10), chain: createMockChain(2, 8), result: Result{pastStart: 2, pastEnd: 8, pastLength: 7}},
+		{name: "X = 10, N = 5, M = 15", current: uint64(10), chain: createMockChain(5, 15), result: Result{pastStart: 5, pastEnd: 10, pastLength: 6, futureStart: 11, futureEnd: 15, futureLength: 5}},
+		{name: "X = 10, N = 10, M = 20", current: uint64(10), chain: createMockChain(10, 20), result: Result{pastStart: 10, pastEnd: 10, pastLength: 1, futureStart: 11, futureEnd: 20, futureLength: 10}},
+	}
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			past, future := splitChain(tc.current, tc.chain)
+			require.Equal(t, len(past), tc.result.pastLength)
+			require.Equal(t, len(future), tc.result.futureLength)
+
+			if len(past) > 0 {
+				// Check if we have expected block/s
+				require.Equal(t, past[0].Number.Uint64(), tc.result.pastStart)
+				require.Equal(t, past[len(past)-1].Number.Uint64(), tc.result.pastEnd)
+			}
+
+			if len(future) > 0 {
+				// Check if we have expected block/s
+				require.Equal(t, future[0].Number.Uint64(), tc.result.futureStart)
+				require.Equal(t, future[len(future)-1].Number.Uint64(), tc.result.futureEnd)
+			}
+		})
+	}
+}
+
+//nolint:gocognit
+func TestSplitChainProperties(t *testing.T) {
+	t.Parallel()
+
+	// Current chain is at block: X
+	// Incoming chain is represented as [N, M]
+
+	currentChain := []int{0, 1, 2, 3, 10, 100} // blocks starting from genesis
+	blockDiffs := []int{0, 1, 2, 3, 4, 5, 9, 10, 11, 12, 90, 100, 101, 102}
+
+	caseParams := make(map[int]map[int]map[int]struct{}) // X -> N -> M
+
+	for _, current := range currentChain {
+		// past cases only + past to current
+		for _, diff := range blockDiffs {
+			from := current - diff
+
+			// use int type for everything to not care about underflow
+			if from < 0 {
+				continue
+			}
+
+			for _, diff := range blockDiffs {
+				to := current - diff
+
+				if to >= from {
+					addTestCaseParams(caseParams, current, from, to)
+				}
+			}
+		}
+
+		// future only + current to future
+		for _, diff := range blockDiffs {
+			from := current + diff
+
+			if from < 0 {
+				continue
+			}
+
+			for _, diff := range blockDiffs {
+				to := current + diff
+
+				if to >= from {
+					addTestCaseParams(caseParams, current, from, to)
+				}
+			}
+		}
+
+		// past-current-future
+		for _, diff := range blockDiffs {
+			from := current - diff
+
+			if from < 0 {
+				continue
+			}
+
+			for _, diff := range blockDiffs {
+				to := current + diff
+
+				if to >= from {
+					addTestCaseParams(caseParams, current, from, to)
+				}
+			}
+		}
+	}
+
+	type testCase struct {
+		current     int
+		remoteStart int
+		remoteEnd   int
+	}
+
+	var ts []testCase
+
+	// X -> N -> M
+	for x, nm := range caseParams {
+		for n, mMap := range nm {
+			for m := range mMap {
+				ts = append(ts, testCase{x, n, m})
+			}
+		}
+	}
+
+	//nolint:paralleltest
+	for i, tc := range ts {
+		tc := tc
+
+		name := fmt.Sprintf("test case: index = %d, X = %d, N = %d, M = %d", i, tc.current, tc.remoteStart, tc.remoteEnd)
+
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			chain := createMockChain(uint64(tc.remoteStart), uint64(tc.remoteEnd))
+
+			past, future := splitChain(uint64(tc.current), chain)
+
+			// properties
+			if len(past) > 0 {
+				// Check if the chain is ordered
+				isOrdered := sort.SliceIsSorted(past, func(i, j int) bool {
+					return past[i].Number.Uint64() < past[j].Number.Uint64()
+				})
+
+				require.True(t, isOrdered, "an ordered past chain expected: %v", past)
+
+				isSequential := sort.SliceIsSorted(past, func(i, j int) bool {
+					return past[i].Number.Uint64() == past[j].Number.Uint64()-1
+				})
+
+				require.True(t, isSequential, "a sequential past chain expected: %v", past)
+
+				// Check if current block >= past chain's last block
+				require.Equal(t, past[len(past)-1].Number.Uint64() <= uint64(tc.current), true)
+			}
+
+			if len(future) > 0 {
+				// Check if the chain is ordered
+				isOrdered := sort.SliceIsSorted(future, func(i, j int) bool {
+					return future[i].Number.Uint64() < future[j].Number.Uint64()
+				})
+
+				require.True(t, isOrdered, "an ordered future chain expected: %v", future)
+
+				isSequential := sort.SliceIsSorted(future, func(i, j int) bool {
+					return future[i].Number.Uint64() == future[j].Number.Uint64()-1
+				})
+
+				require.True(t, isSequential, "a sequential future chain expected: %v", future)
+
+				// Check if future chain's first block > current block
+				require.Equal(t, future[len(future)-1].Number.Uint64() > uint64(tc.current), true)
+			}
+
+			// Check if both chains are continuous
+			if len(past) > 0 && len(future) > 0 {
+				require.Equal(t, past[len(past)-1].Number.Uint64(), future[0].Number.Uint64()-1)
+			}
+
+			// Check if we get the original chain on appending both
+			gotChain := append(past, future...)
+			require.Equal(t, reflect.DeepEqual(gotChain, chain), true)
+		})
+	}
+}
+
+// createMockChain returns a chain with dummy headers
+// starting from `start` to `end` (inclusive)
+func createMockChain(start, end uint64) []*types.Header {
+	var (
+		i     uint64
+		idx   uint64
+		chain []*types.Header = make([]*types.Header, end-start+1)
+	)
+
+	for i = start; i <= end; i++ {
+		header := &types.Header{
+			Number: big.NewInt(int64(i)),
+			Time:   uint64(time.Now().UnixMicro()) + i,
+		}
+		chain[idx] = header
+		idx++
+	}
+
+	return chain
+}
+
+// mXNM should be initialized
+func addTestCaseParams(mXNM map[int]map[int]map[int]struct{}, x, n, m int) {
+	//nolint:ineffassign
+	mNM, ok := mXNM[x]
+	if !ok {
+		mNM = make(map[int]map[int]struct{})
+		mXNM[x] = mNM
+	}
+
+	//nolint:ineffassign
+	_, ok = mNM[n]
+	if !ok {
+		mM := make(map[int]struct{})
+		mNM[n] = mM
+	}
+
+	mXNM[x][n][m] = struct{}{}
 }
diff --git a/eth/ethconfig/config.go b/eth/ethconfig/config.go
index 091600d8b5..d51e293413 100644
--- a/eth/ethconfig/config.go
+++ b/eth/ethconfig/config.go
@@ -30,7 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/beacon"
 	"github.com/ethereum/go-ethereum/consensus/bor"
 	"github.com/ethereum/go-ethereum/consensus/bor/contract"
-	"github.com/ethereum/go-ethereum/consensus/bor/heimdall"
+	"github.com/ethereum/go-ethereum/consensus/bor/heimdall" //nolint:typecheck
 	"github.com/ethereum/go-ethereum/consensus/bor/heimdall/span"
 	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
diff --git a/eth/filters/bor_api.go b/eth/filters/bor_api.go
index 517ff894f4..d6f0aea45a 100644
--- a/eth/filters/bor_api.go
+++ b/eth/filters/bor_api.go
@@ -59,8 +59,9 @@ func (api *PublicFilterAPI) NewDeposits(ctx context.Context, crit ethereum.State
 	}
 
 	rpcSub := notifier.CreateSubscription()
+
 	go func() {
-		stateSyncData := make(chan *types.StateSyncData)
+		stateSyncData := make(chan *types.StateSyncData, 10)
 		stateSyncSub := api.events.SubscribeNewDeposits(stateSyncData)
 
 		for {
diff --git a/eth/gasprice/gasprice_test.go b/eth/gasprice/gasprice_test.go
index c0d3c6b603..134168b885 100644
--- a/eth/gasprice/gasprice_test.go
+++ b/eth/gasprice/gasprice_test.go
@@ -144,7 +144,7 @@ func newTestBackend(t *testing.T, londonBlock *big.Int, pending bool) *testBacke
 	// Construct testing chain
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.Commit(diskdb)
-	chain, err := core.NewBlockChain(diskdb, &core.CacheConfig{TrieCleanNoPrefetch: true}, gspec.Config, engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(diskdb, &core.CacheConfig{TrieCleanNoPrefetch: true}, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("Failed to create local chain, %v", err)
 	}
diff --git a/eth/handler.go b/eth/handler.go
index ab95f5f769..a9c4f4eb1f 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -24,6 +24,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/beacon"
@@ -31,7 +32,6 @@ import (
 	"github.com/ethereum/go-ethereum/core/forkid"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth/downloader"
-	"github.com/ethereum/go-ethereum/eth/downloader/whitelist"
 	"github.com/ethereum/go-ethereum/eth/fetcher"
 	"github.com/ethereum/go-ethereum/eth/protocols/eth"
 	"github.com/ethereum/go-ethereum/eth/protocols/snap"
@@ -91,6 +91,7 @@ type handlerConfig struct {
 	EthAPI     *ethapi.PublicBlockChainAPI // EthAPI to interact
 
 	PeerRequiredBlocks map[uint64]common.Hash // Hard coded map of required block hashes for sync challenges
+	checker            ethereum.ChainValidator
 }
 
 type handler struct {
@@ -202,7 +203,7 @@ func newHandler(config *handlerConfig) (*handler, error) {
 	// sync is requested. The downloader is responsible for deallocating the state
 	// bloom when it's done.
 	// todo: it'd better to extract maxCapacity into config
-	h.downloader = downloader.New(h.checkpointNumber, config.Database, h.eventMux, h.chain, nil, h.removePeer, success, whitelist.NewService(10))
+	h.downloader = downloader.New(h.checkpointNumber, config.Database, h.eventMux, h.chain, nil, h.removePeer, success, config.checker)
 
 	// Construct the fetcher (short sync)
 	validator := func(header *types.Header) error {
diff --git a/eth/handler_bor.go b/eth/handler_bor.go
index eca4b0c7eb..35d6e00bfc 100644
--- a/eth/handler_bor.go
+++ b/eth/handler_bor.go
@@ -13,6 +13,14 @@ import (
 )
 
 var (
+	// errCheckpointCount is returned when we are unable to fetch
+	// the checkpoint count from local heimdall.
+	errCheckpointCount = errors.New("failed to fetch checkpoint count")
+
+	// errNoCheckpoint is returned when there is not checkpoint proposed
+	// by heimdall yet or heimdall is not in sync
+	errNoCheckpoint = errors.New("no checkpoint proposed")
+
 	// errCheckpoint is returned when we are unable to fetch the
 	// latest checkpoint from the local heimdall.
 	errCheckpoint = errors.New("failed to fetch latest checkpoint")
@@ -33,43 +41,78 @@ var (
 	errEndBlock = errors.New("failed to get end block")
 )
 
-// fetchWhitelistCheckpoint fetched the latest checkpoint from it's local heimdall
+// fetchWhitelistCheckpoints fetches the latest checkpoint/s from it's local heimdall
 // and verifies the data against bor data.
-func (h *ethHandler) fetchWhitelistCheckpoint(ctx context.Context, bor *bor.Bor) (uint64, common.Hash, error) {
-	// check for checkpoint whitelisting: bor
-	checkpoint, err := bor.HeimdallClient.FetchLatestCheckpoint(ctx)
+func (h *ethHandler) fetchWhitelistCheckpoints(ctx context.Context, bor *bor.Bor, first bool) ([]uint64, []common.Hash, error) {
+	// Create an array for block number and block hashes
+	//nolint:prealloc
+	var (
+		blockNums   []uint64      = make([]uint64, 0)
+		blockHashes []common.Hash = make([]common.Hash, 0)
+	)
+
+	// Fetch the checkpoint count from heimdall
+	count, err := bor.HeimdallClient.FetchCheckpointCount(ctx)
 	if err != nil {
-		log.Debug("Failed to fetch latest checkpoint for whitelisting")
-		return 0, common.Hash{}, errCheckpoint
+		log.Debug("Failed to fetch checkpoint count for whitelisting", "err", err)
+		return blockNums, blockHashes, errCheckpointCount
 	}
 
-	// check if we have the checkpoint blocks
-	head := h.ethAPI.BlockNumber()
-	if head < hexutil.Uint64(checkpoint.EndBlock.Uint64()) {
-		log.Debug("Head block behind checkpoint block", "head", head, "checkpoint end block", checkpoint.EndBlock)
-		return 0, common.Hash{}, errMissingCheckpoint
+	if count == 0 {
+		return blockNums, blockHashes, errNoCheckpoint
 	}
 
-	// verify the root hash of checkpoint
-	roothash, err := h.ethAPI.GetRootHash(ctx, checkpoint.StartBlock.Uint64(), checkpoint.EndBlock.Uint64())
-	if err != nil {
-		log.Debug("Failed to get root hash of checkpoint while whitelisting")
-		return 0, common.Hash{}, errRootHash
+	// If we're in the first iteration, we'll fetch last 10 checkpoints, else only the latest one
+	iterations := 1
+	if first {
+		iterations = 10
 	}
 
-	if roothash != checkpoint.RootHash.String()[2:] {
-		log.Warn("Checkpoint root hash mismatch while whitelisting", "expected", checkpoint.RootHash.String()[2:], "got", roothash)
-		return 0, common.Hash{}, errCheckpointRootHashMismatch
+	for i := 0; i < iterations; i++ {
+		// If we don't have any checkpoints in heimdall, break
+		if count == 0 {
+			break
+		}
+
+		// fetch `count` indexed checkpoint from heimdall
+		checkpoint, err := bor.HeimdallClient.FetchCheckpoint(ctx, count)
+		if err != nil {
+			log.Debug("Failed to fetch latest checkpoint for whitelisting", "err", err)
+			return blockNums, blockHashes, errCheckpoint
+		}
+
+		// check if we have the checkpoint blocks
+		head := h.ethAPI.BlockNumber()
+		if head < hexutil.Uint64(checkpoint.EndBlock.Uint64()) {
+			log.Debug("Head block behind checkpoint block", "head", head, "checkpoint end block", checkpoint.EndBlock)
+			return blockNums, blockHashes, errMissingCheckpoint
+		}
+
+		// verify the root hash of checkpoint
+		roothash, err := h.ethAPI.GetRootHash(ctx, checkpoint.StartBlock.Uint64(), checkpoint.EndBlock.Uint64())
+		if err != nil {
+			log.Debug("Failed to get root hash of checkpoint while whitelisting", "err", err)
+			return blockNums, blockHashes, errRootHash
+		}
+
+		if roothash != checkpoint.RootHash.String()[2:] {
+			log.Warn("Checkpoint root hash mismatch while whitelisting", "expected", checkpoint.RootHash.String()[2:], "got", roothash)
+			return blockNums, blockHashes, errCheckpointRootHashMismatch
+		}
+
+		// fetch the end checkpoint block hash
+		block, err := h.ethAPI.GetBlockByNumber(ctx, rpc.BlockNumber(checkpoint.EndBlock.Uint64()), false)
+		if err != nil {
+			log.Debug("Failed to get end block hash of checkpoint while whitelisting", "err", err)
+			return blockNums, blockHashes, errEndBlock
+		}
+
+		hash := fmt.Sprintf("%v", block["hash"])
+
+		blockNums = append(blockNums, checkpoint.EndBlock.Uint64())
+		blockHashes = append(blockHashes, common.HexToHash(hash))
+		count--
 	}
 
-	// fetch the end checkpoint block hash
-	block, err := h.ethAPI.GetBlockByNumber(context.Background(), rpc.BlockNumber(checkpoint.EndBlock.Uint64()), false)
-	if err != nil {
-		log.Debug("Failed to get end block hash of checkpoint while whitelisting")
-		return 0, common.Hash{}, errEndBlock
-	}
-
-	hash := fmt.Sprintf("%v", block["hash"])
-
-	return checkpoint.EndBlock.Uint64(), common.HexToHash(hash), nil
+	return blockNums, blockHashes, nil
 }
diff --git a/eth/handler_eth_test.go b/eth/handler_eth_test.go
index 7d5027ae77..6634b26871 100644
--- a/eth/handler_eth_test.go
+++ b/eth/handler_eth_test.go
@@ -105,8 +105,8 @@ func testForkIDSplit(t *testing.T, protocol uint) {
 		genesisNoFork  = gspecNoFork.MustCommit(dbNoFork)
 		genesisProFork = gspecProFork.MustCommit(dbProFork)
 
-		chainNoFork, _  = core.NewBlockChain(dbNoFork, nil, configNoFork, engine, vm.Config{}, nil, nil)
-		chainProFork, _ = core.NewBlockChain(dbProFork, nil, configProFork, engine, vm.Config{}, nil, nil)
+		chainNoFork, _  = core.NewBlockChain(dbNoFork, nil, configNoFork, engine, vm.Config{}, nil, nil, nil)
+		chainProFork, _ = core.NewBlockChain(dbProFork, nil, configProFork, engine, vm.Config{}, nil, nil, nil)
 
 		blocksNoFork, _  = core.GenerateChain(configNoFork, genesisNoFork, engine, dbNoFork, 2, nil)
 		blocksProFork, _ = core.GenerateChain(configProFork, genesisProFork, engine, dbProFork, 2, nil)
diff --git a/eth/handler_test.go b/eth/handler_test.go
index d967b6df93..c6d7811d10 100644
--- a/eth/handler_test.go
+++ b/eth/handler_test.go
@@ -138,7 +138,7 @@ func newTestHandlerWithBlocks(blocks int) *testHandler {
 		Alloc:  core.GenesisAlloc{testAddr: {Balance: big.NewInt(1000000)}},
 	}).MustCommit(db)
 
-	chain, _ := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 
 	bs, _ := core.GenerateChain(params.TestChainConfig, chain.Genesis(), ethash.NewFaker(), db, blocks, nil)
 	if _, err := chain.InsertChain(bs); err != nil {
diff --git a/eth/protocols/eth/handler_test.go b/eth/protocols/eth/handler_test.go
index 55e612b801..0bbe9f66a9 100644
--- a/eth/protocols/eth/handler_test.go
+++ b/eth/protocols/eth/handler_test.go
@@ -68,7 +68,7 @@ func newTestBackendWithGenerator(blocks int, generator func(int, *core.BlockGen)
 		Alloc:  core.GenesisAlloc{testAddr: {Balance: big.NewInt(100_000_000_000_000_000)}},
 	}).MustCommit(db)
 
-	chain, _ := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db, nil, params.TestChainConfig, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 
 	bs, _ := core.GenerateChain(params.TestChainConfig, chain.Genesis(), ethash.NewFaker(), db, blocks, generator)
 	if _, err := chain.InsertChain(bs); err != nil {
diff --git a/eth/tracers/api_test.go b/eth/tracers/api_test.go
index a3c0a72494..d2ed9c2179 100644
--- a/eth/tracers/api_test.go
+++ b/eth/tracers/api_test.go
@@ -81,7 +81,7 @@ func newTestBackend(t *testing.T, n int, gspec *core.Genesis, generator func(i i
 		SnapshotLimit:     0,
 		TrieDirtyDisabled: true, // Archive mode
 	}
-	chain, err := core.NewBlockChain(backend.chaindb, cacheConfig, backend.chainConfig, backend.engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(backend.chaindb, cacheConfig, backend.chainConfig, backend.engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
diff --git a/interfaces.go b/interfaces.go
index 94a2492ae1..ff6d80b1ec 100644
--- a/interfaces.go
+++ b/interfaces.go
@@ -238,3 +238,12 @@ type StateSyncFilter struct {
 	ID       uint64
 	Contract common.Address
 }
+
+// interface for whitelist service
+type ChainValidator interface {
+	IsValidPeer(remoteHeader *types.Header, fetchHeadersByNumber func(number uint64, amount int, skip int, reverse bool) ([]*types.Header, []common.Hash, error)) (bool, error)
+	IsValidChain(currentHeader *types.Header, chain []*types.Header) bool
+	ProcessCheckpoint(endBlockNum uint64, endBlockHash common.Hash)
+	GetCheckpointWhitelist() map[uint64]common.Hash
+	PurgeCheckpointWhitelist()
+}
diff --git a/internal/cli/bootnode.go b/internal/cli/bootnode.go
index 9e1a0fcde9..d1dc1c2fd9 100644
--- a/internal/cli/bootnode.go
+++ b/internal/cli/bootnode.go
@@ -4,7 +4,6 @@ import (
 	"crypto/ecdsa"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/signal"
@@ -162,7 +161,7 @@ func (b *BootnodeCommand) Run(args []string) int {
 			}
 			// save the public key
 			pubRaw := fmt.Sprintf("%x", crypto.FromECDSAPub(&nodeKey.PublicKey)[1:])
-			if err := ioutil.WriteFile(filepath.Join(path, "pub.key"), []byte(pubRaw), 0600); err != nil {
+			if err := os.WriteFile(filepath.Join(path, "pub.key"), []byte(pubRaw), 0600); err != nil {
 				b.UI.Error(fmt.Sprintf("failed to write node pub key: %v", err))
 				return 1
 			}
diff --git a/internal/cli/debug_test.go b/internal/cli/debug_test.go
index f77cf839ac..94765ddba7 100644
--- a/internal/cli/debug_test.go
+++ b/internal/cli/debug_test.go
@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"github.com/mitchellh/cli"
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/ethereum/go-ethereum/internal/cli/server"
 )
@@ -30,7 +30,7 @@ func TestCommand_DebugBlock(t *testing.T) {
 
 	// start the mock server
 	srv, err := server.CreateMockServer(config)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 
 	defer server.CloseMockServer(srv)
 
@@ -53,7 +53,7 @@ func TestCommand_DebugBlock(t *testing.T) {
 	start := time.Now()
 	dst1 := path.Join(output, prefix+time.Now().UTC().Format("2006-01-02-150405Z"), "block.json")
 	res := traceBlock(port, 1, output)
-	assert.Equal(t, 0, res)
+	require.Equal(t, 0, res)
 	t.Logf("Completed trace of block %d in %d ms at %s", 1, time.Since(start).Milliseconds(), dst1)
 
 	// adding this to avoid debug directory name conflicts
@@ -64,14 +64,14 @@ func TestCommand_DebugBlock(t *testing.T) {
 	latestBlock := srv.GetLatestBlockNumber().Int64()
 	dst2 := path.Join(output, prefix+time.Now().UTC().Format("2006-01-02-150405Z"), "block.json")
 	res = traceBlock(port, latestBlock, output)
-	assert.Equal(t, 0, res)
+	require.Equal(t, 0, res)
 	t.Logf("Completed trace of block %d in %d ms at %s", latestBlock, time.Since(start).Milliseconds(), dst2)
 
 	// verify if the trace files are created
 	done := verify(dst1)
-	assert.Equal(t, true, done)
+	require.Equal(t, true, done)
 	done = verify(dst2)
-	assert.Equal(t, true, done)
+	require.Equal(t, true, done)
 
 	// delete the traces
 	deleteTraces(output)
diff --git a/internal/cli/flagset/flagset.go b/internal/cli/flagset/flagset.go
index b57fff9996..0c19fa9758 100644
--- a/internal/cli/flagset/flagset.go
+++ b/internal/cli/flagset/flagset.go
@@ -202,10 +202,11 @@ func (f *Flagset) BigIntFlag(b *BigIntFlag) {
 }
 
 type SliceStringFlag struct {
-	Name  string
-	Usage string
-	Value *[]string
-	Group string
+	Name    string
+	Usage   string
+	Value   *[]string
+	Default []string
+	Group   string
 }
 
 func (i *SliceStringFlag) String() string {
@@ -217,8 +218,8 @@ func (i *SliceStringFlag) String() string {
 }
 
 func (i *SliceStringFlag) Set(value string) error {
-	*i.Value = append(*i.Value, strings.Split(value, ",")...)
-
+	// overwritting insted of appending
+	*i.Value = strings.Split(value, ",")
 	return nil
 }
 
diff --git a/internal/cli/flagset/flagset_test.go b/internal/cli/flagset/flagset_test.go
index 2f046c3248..118361320d 100644
--- a/internal/cli/flagset/flagset_test.go
+++ b/internal/cli/flagset/flagset_test.go
@@ -23,14 +23,17 @@ func TestFlagsetBool(t *testing.T) {
 func TestFlagsetSliceString(t *testing.T) {
 	f := NewFlagSet("")
 
-	value := []string{}
+	value := []string{"a", "b", "c"}
 	f.SliceStringFlag(&SliceStringFlag{
-		Name:  "flag",
-		Value: &value,
+		Name:    "flag",
+		Value:   &value,
+		Default: value,
 	})
 
-	assert.NoError(t, f.Parse([]string{"--flag", "a,b", "--flag", "c"}))
+	assert.NoError(t, f.Parse([]string{}))
 	assert.Equal(t, value, []string{"a", "b", "c"})
+	assert.NoError(t, f.Parse([]string{"--flag", "a,b"}))
+	assert.Equal(t, value, []string{"a", "b"})
 }
 
 func TestFlagsetDuration(t *testing.T) {
diff --git a/internal/cli/markdown_test.go b/internal/cli/markdown_test.go
index 30c272a220..24a0e40e11 100644
--- a/internal/cli/markdown_test.go
+++ b/internal/cli/markdown_test.go
@@ -3,12 +3,12 @@ package cli
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestCodeBlock(t *testing.T) {
 	t.Parallel()
-	assert := assert.New(t)
+	assert := require.New(t)
 
 	lines := []string{
 		"abc",
diff --git a/internal/cli/server/chains/chain.go b/internal/cli/server/chains/chain.go
index d6717f5893..582ef64d21 100644
--- a/internal/cli/server/chains/chain.go
+++ b/internal/cli/server/chains/chain.go
@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -50,7 +49,7 @@ func GetChain(name string) (*Chain, error) {
 }
 
 func ImportFromFile(filename string) (*Chain, error) {
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}
diff --git a/internal/cli/server/config.go b/internal/cli/server/config.go
index 347287e22f..fdf253a37e 100644
--- a/internal/cli/server/config.go
+++ b/internal/cli/server/config.go
@@ -40,8 +40,8 @@ type Config struct {
 	// Chain is the chain to sync with
 	Chain string `hcl:"chain,optional"`
 
-	// Name, or identity of the node
-	Name string `hcl:"name,optional"`
+	// Identity of the node
+	Identity string `hcl:"identity,optional"`
 
 	// RequiredBlocks is a list of required (block number, hash) pairs to accept
 	RequiredBlocks map[string]string `hcl:"requiredblocks,optional"`
@@ -61,8 +61,8 @@ type Config struct {
 	// GcMode selects the garbage collection mode for the trie
 	GcMode string `hcl:"gc-mode,optional"`
 
-	// NoSnapshot disables the snapshot database mode
-	NoSnapshot bool `hcl:"no-snapshot,optional"`
+	// Snapshot disables/enables the snapshot database mode
+	Snapshot bool `hcl:"snapshot,optional"`
 
 	// Ethstats is the address of the ethstats server to send telemetry
 	Ethstats string `hcl:"ethstats,optional"`
@@ -217,12 +217,6 @@ type JsonRPCConfig struct {
 	// IPCPath is the path of the ipc endpoint
 	IPCPath string `hcl:"ipc-path,optional"`
 
-	// VHost is the list of valid virtual hosts
-	VHost []string `hcl:"vhost,optional"`
-
-	// Cors is the list of Cors endpoints
-	Cors []string `hcl:"cors,optional"`
-
 	// GasCap is the global gas cap for eth-call variants.
 	GasCap uint64 `hcl:"gas-cap,optional"`
 
@@ -232,10 +226,10 @@ type JsonRPCConfig struct {
 	// Http has the json-rpc http related settings
 	Http *APIConfig `hcl:"http,block"`
 
-	// Http has the json-rpc websocket related settings
+	// Ws has the json-rpc websocket related settings
 	Ws *APIConfig `hcl:"ws,block"`
 
-	// Http has the json-rpc graphql related settings
+	// Graphql has the json-rpc graphql related settings
 	Graphql *APIConfig `hcl:"graphql,block"`
 }
 
@@ -258,7 +252,13 @@ type APIConfig struct {
 	Host string `hcl:"host,optional"`
 
 	// Modules is the list of enabled api modules
-	Modules []string `hcl:"modules,optional"`
+	API []string `hcl:"modules,optional"`
+
+	// VHost is the list of valid virtual hosts
+	VHost []string `hcl:"vhost,optional"`
+
+	// Cors is the list of Cors endpoints
+	Cors []string `hcl:"cors,optional"`
 }
 
 type GpoConfig struct {
@@ -387,7 +387,7 @@ type DeveloperConfig struct {
 func DefaultConfig() *Config {
 	return &Config{
 		Chain:          "mainnet",
-		Name:           Hostname(),
+		Identity:       Hostname(),
 		RequiredBlocks: map[string]string{},
 		LogLevel:       "INFO",
 		DataDir:        defaultDataDir(),
@@ -412,9 +412,9 @@ func DefaultConfig() *Config {
 			URL:     "http://localhost:1317",
 			Without: false,
 		},
-		SyncMode:   "full",
-		GcMode:     "full",
-		NoSnapshot: false,
+		SyncMode: "full",
+		GcMode:   "full",
+		Snapshot: true,
 		TxPool: &TxPoolConfig{
 			Locals:       []string{},
 			NoLocals:     false,
@@ -444,8 +444,6 @@ func DefaultConfig() *Config {
 		JsonRPC: &JsonRPCConfig{
 			IPCDisable: false,
 			IPCPath:    "",
-			Cors:       []string{"*"},
-			VHost:      []string{"*"},
 			GasCap:     ethconfig.Defaults.RPCGasCap,
 			TxFeeCap:   ethconfig.Defaults.RPCTxFeeCap,
 			Http: &APIConfig{
@@ -453,17 +451,23 @@ func DefaultConfig() *Config {
 				Port:    8545,
 				Prefix:  "",
 				Host:    "localhost",
-				Modules: []string{"eth", "net", "web3", "txpool", "bor"},
+				API:     []string{"eth", "net", "web3", "txpool", "bor"},
+				Cors:    []string{"*"},
+				VHost:   []string{"*"},
 			},
 			Ws: &APIConfig{
 				Enabled: false,
 				Port:    8546,
 				Prefix:  "",
 				Host:    "localhost",
-				Modules: []string{"web3", "net"},
+				API:     []string{"web3", "net"},
+				Cors:    []string{"*"},
+				VHost:   []string{"*"},
 			},
 			Graphql: &APIConfig{
 				Enabled: false,
+				Cors:    []string{"*"},
+				VHost:   []string{"*"},
 			},
 		},
 		Ethstats: "",
@@ -864,7 +868,7 @@ func (c *Config) buildEth(stack *node.Node, accountManager *accounts.Manager) (*
 	}
 
 	// snapshot disable check
-	if c.NoSnapshot {
+	if !c.Snapshot {
 		if n.SyncMode == downloader.SnapSync {
 			log.Info("Snap sync requested, enabling --snapshot")
 		} else {
@@ -908,15 +912,15 @@ func (c *Config) buildNode() (*node.Config, error) {
 			ListenAddr:      c.P2P.Bind + ":" + strconv.Itoa(int(c.P2P.Port)),
 			DiscoveryV5:     c.P2P.Discovery.V5Enabled,
 		},
-		HTTPModules:         c.JsonRPC.Http.Modules,
-		HTTPCors:            c.JsonRPC.Cors,
-		HTTPVirtualHosts:    c.JsonRPC.VHost,
+		HTTPModules:         c.JsonRPC.Http.API,
+		HTTPCors:            c.JsonRPC.Http.Cors,
+		HTTPVirtualHosts:    c.JsonRPC.Http.VHost,
 		HTTPPathPrefix:      c.JsonRPC.Http.Prefix,
-		WSModules:           c.JsonRPC.Ws.Modules,
-		WSOrigins:           c.JsonRPC.Cors,
+		WSModules:           c.JsonRPC.Ws.API,
+		WSOrigins:           c.JsonRPC.Ws.Cors,
 		WSPathPrefix:        c.JsonRPC.Ws.Prefix,
-		GraphQLCors:         c.JsonRPC.Cors,
-		GraphQLVirtualHosts: c.JsonRPC.VHost,
+		GraphQLCors:         c.JsonRPC.Graphql.Cors,
+		GraphQLVirtualHosts: c.JsonRPC.Graphql.VHost,
 	}
 
 	// dev mode
@@ -999,7 +1003,7 @@ func (c *Config) buildNode() (*node.Config, error) {
 
 func (c *Config) Merge(cc ...*Config) error {
 	for _, elem := range cc {
-		if err := mergo.Merge(c, elem, mergo.WithOverwriteWithEmptyValue, mergo.WithAppendSlice); err != nil {
+		if err := mergo.Merge(c, elem, mergo.WithOverwriteWithEmptyValue); err != nil {
 			return fmt.Errorf("failed to merge configurations: %v", err)
 		}
 	}
diff --git a/internal/cli/server/config_test.go b/internal/cli/server/config_test.go
index 94c4496c03..c1c6c4ef4a 100644
--- a/internal/cli/server/config_test.go
+++ b/internal/cli/server/config_test.go
@@ -22,8 +22,8 @@ func TestConfigDefault(t *testing.T) {
 
 func TestConfigMerge(t *testing.T) {
 	c0 := &Config{
-		Chain:      "0",
-		NoSnapshot: true,
+		Chain:    "0",
+		Snapshot: true,
 		RequiredBlocks: map[string]string{
 			"a": "b",
 		},
@@ -54,8 +54,8 @@ func TestConfigMerge(t *testing.T) {
 	}
 
 	expected := &Config{
-		Chain:      "1",
-		NoSnapshot: false,
+		Chain:    "1",
+		Snapshot: false,
 		RequiredBlocks: map[string]string{
 			"a": "b",
 			"b": "c",
@@ -64,7 +64,6 @@ func TestConfigMerge(t *testing.T) {
 			MaxPeers: 10,
 			Discovery: &P2PDiscovery{
 				StaticNodes: []string{
-					"a",
 					"b",
 				},
 			},
diff --git a/internal/cli/server/flags.go b/internal/cli/server/flags.go
index 21e9a38cb9..e85428b9ee 100644
--- a/internal/cli/server/flags.go
+++ b/internal/cli/server/flags.go
@@ -16,10 +16,10 @@ func (c *Command) Flags() *flagset.Flagset {
 		Default: c.cliConfig.Chain,
 	})
 	f.StringFlag(&flagset.StringFlag{
-		Name:    "name",
+		Name:    "identity",
 		Usage:   "Name/Identity of the node",
-		Value:   &c.cliConfig.Name,
-		Default: c.cliConfig.Name,
+		Value:   &c.cliConfig.Identity,
+		Default: c.cliConfig.Identity,
 	})
 	f.StringFlag(&flagset.StringFlag{
 		Name:    "log-level",
@@ -61,10 +61,10 @@ func (c *Command) Flags() *flagset.Flagset {
 		Value: &c.cliConfig.RequiredBlocks,
 	})
 	f.BoolFlag(&flagset.BoolFlag{
-		Name:    "no-snapshot",
-		Usage:   `Disables the snapshot-database mode (default = false)`,
-		Value:   &c.cliConfig.NoSnapshot,
-		Default: c.cliConfig.NoSnapshot,
+		Name:    "snapshot",
+		Usage:   `Disables/Enables the snapshot-database mode (default = true)`,
+		Value:   &c.cliConfig.Snapshot,
+		Default: c.cliConfig.Snapshot,
 	})
 
 	// heimdall
@@ -83,10 +83,11 @@ func (c *Command) Flags() *flagset.Flagset {
 
 	// txpool options
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "txpool.locals",
-		Usage: "Comma separated accounts to treat as locals (no flush, priority inclusion)",
-		Value: &c.cliConfig.TxPool.Locals,
-		Group: "Transaction Pool",
+		Name:    "txpool.locals",
+		Usage:   "Comma separated accounts to treat as locals (no flush, priority inclusion)",
+		Value:   &c.cliConfig.TxPool.Locals,
+		Default: c.cliConfig.TxPool.Locals,
+		Group:   "Transaction Pool",
 	})
 	f.BoolFlag(&flagset.BoolFlag{
 		Name:    "txpool.nolocals",
@@ -329,16 +330,46 @@ func (c *Command) Flags() *flagset.Flagset {
 		Group:   "JsonRPC",
 	})
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "jsonrpc.corsdomain",
-		Usage: "Comma separated list of domains from which to accept cross origin requests (browser enforced)",
-		Value: &c.cliConfig.JsonRPC.Cors,
-		Group: "JsonRPC",
+		Name:    "http.corsdomain",
+		Usage:   "Comma separated list of domains from which to accept cross origin requests (browser enforced)",
+		Value:   &c.cliConfig.JsonRPC.Http.Cors,
+		Default: c.cliConfig.JsonRPC.Http.Cors,
+		Group:   "JsonRPC",
 	})
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "jsonrpc.vhosts",
-		Usage: "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.",
-		Value: &c.cliConfig.JsonRPC.VHost,
-		Group: "JsonRPC",
+		Name:    "http.vhosts",
+		Usage:   "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.",
+		Value:   &c.cliConfig.JsonRPC.Http.VHost,
+		Default: c.cliConfig.JsonRPC.Http.VHost,
+		Group:   "JsonRPC",
+	})
+	f.SliceStringFlag(&flagset.SliceStringFlag{
+		Name:    "ws.corsdomain",
+		Usage:   "Comma separated list of domains from which to accept cross origin requests (browser enforced)",
+		Value:   &c.cliConfig.JsonRPC.Ws.Cors,
+		Default: c.cliConfig.JsonRPC.Ws.Cors,
+		Group:   "JsonRPC",
+	})
+	f.SliceStringFlag(&flagset.SliceStringFlag{
+		Name:    "ws.vhosts",
+		Usage:   "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.",
+		Value:   &c.cliConfig.JsonRPC.Ws.VHost,
+		Default: c.cliConfig.JsonRPC.Ws.VHost,
+		Group:   "JsonRPC",
+	})
+	f.SliceStringFlag(&flagset.SliceStringFlag{
+		Name:    "graphql.corsdomain",
+		Usage:   "Comma separated list of domains from which to accept cross origin requests (browser enforced)",
+		Value:   &c.cliConfig.JsonRPC.Graphql.Cors,
+		Default: c.cliConfig.JsonRPC.Graphql.Cors,
+		Group:   "JsonRPC",
+	})
+	f.SliceStringFlag(&flagset.SliceStringFlag{
+		Name:    "graphql.vhosts",
+		Usage:   "Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard.",
+		Value:   &c.cliConfig.JsonRPC.Graphql.VHost,
+		Default: c.cliConfig.JsonRPC.Graphql.VHost,
+		Group:   "JsonRPC",
 	})
 
 	// http options
@@ -371,10 +402,11 @@ func (c *Command) Flags() *flagset.Flagset {
 		Group:   "JsonRPC",
 	})
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "http.modules",
-		Usage: "API's offered over the HTTP-RPC interface",
-		Value: &c.cliConfig.JsonRPC.Http.Modules,
-		Group: "JsonRPC",
+		Name:    "http.api",
+		Usage:   "API's offered over the HTTP-RPC interface",
+		Value:   &c.cliConfig.JsonRPC.Http.API,
+		Default: c.cliConfig.JsonRPC.Http.API,
+		Group:   "JsonRPC",
 	})
 
 	// ws options
@@ -407,10 +439,11 @@ func (c *Command) Flags() *flagset.Flagset {
 		Group:   "JsonRPC",
 	})
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "ws.modules",
-		Usage: "API's offered over the WS-RPC interface",
-		Value: &c.cliConfig.JsonRPC.Ws.Modules,
-		Group: "JsonRPC",
+		Name:    "ws.api",
+		Usage:   "API's offered over the WS-RPC interface",
+		Value:   &c.cliConfig.JsonRPC.Ws.API,
+		Default: c.cliConfig.JsonRPC.Ws.API,
+		Group:   "JsonRPC",
 	})
 
 	// graphql options
@@ -438,10 +471,11 @@ func (c *Command) Flags() *flagset.Flagset {
 		Group:   "P2P",
 	})
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "bootnodes",
-		Usage: "Comma separated enode URLs for P2P discovery bootstrap",
-		Value: &c.cliConfig.P2P.Discovery.Bootnodes,
-		Group: "P2P",
+		Name:    "bootnodes",
+		Usage:   "Comma separated enode URLs for P2P discovery bootstrap",
+		Value:   &c.cliConfig.P2P.Discovery.Bootnodes,
+		Default: c.cliConfig.P2P.Discovery.Bootnodes,
+		Group:   "P2P",
 	})
 	f.Uint64Flag(&flagset.Uint64Flag{
 		Name:    "maxpeers",
@@ -581,10 +615,11 @@ func (c *Command) Flags() *flagset.Flagset {
 
 	// account
 	f.SliceStringFlag(&flagset.SliceStringFlag{
-		Name:  "unlock",
-		Usage: "Comma separated list of accounts to unlock",
-		Value: &c.cliConfig.Accounts.Unlock,
-		Group: "Account Management",
+		Name:    "unlock",
+		Usage:   "Comma separated list of accounts to unlock",
+		Value:   &c.cliConfig.Accounts.Unlock,
+		Default: c.cliConfig.Accounts.Unlock,
+		Group:   "Account Management",
 	})
 	f.StringFlag(&flagset.StringFlag{
 		Name:    "password",
diff --git a/internal/cli/server/helper.go b/internal/cli/server/helper.go
index 3a232d3185..428acceea3 100644
--- a/internal/cli/server/helper.go
+++ b/internal/cli/server/helper.go
@@ -2,7 +2,6 @@ package server
 
 import (
 	"fmt"
-	"io/ioutil"
 	"math/rand"
 	"net"
 	"os"
@@ -55,7 +54,7 @@ func CreateMockServer(config *Config) (*Server, error) {
 	config.GRPC.Addr = fmt.Sprintf(":%d", port)
 
 	// datadir
-	datadir, _ := ioutil.TempDir("/tmp", "bor-cli-test")
+	datadir, _ := os.MkdirTemp("/tmp", "bor-cli-test")
 	config.DataDir = datadir
 
 	// find available port for http server
diff --git a/internal/cli/server/server.go b/internal/cli/server/server.go
index 7d5ec2c8f3..77d310061c 100644
--- a/internal/cli/server/server.go
+++ b/internal/cli/server/server.go
@@ -23,8 +23,8 @@ import (
 
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
-	"github.com/ethereum/go-ethereum/consensus/beacon"
-	"github.com/ethereum/go-ethereum/consensus/bor"
+	"github.com/ethereum/go-ethereum/consensus/beacon" //nolint:typecheck
+	"github.com/ethereum/go-ethereum/consensus/bor"    //nolint:typecheck
 	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/eth/tracers"
@@ -182,7 +182,7 @@ func NewServer(config *Config) (*Server, error) {
 
 	// graphql is started from another place
 	if config.JsonRPC.Graphql.Enabled {
-		if err := graphql.New(stack, srv.backend.APIBackend, config.JsonRPC.Cors, config.JsonRPC.VHost); err != nil {
+		if err := graphql.New(stack, srv.backend.APIBackend, config.JsonRPC.Graphql.Cors, config.JsonRPC.Graphql.VHost); err != nil {
 			return nil, fmt.Errorf("failed to register the GraphQL service: %v", err)
 		}
 	}
@@ -201,7 +201,7 @@ func NewServer(config *Config) (*Server, error) {
 		}
 	}
 
-	if err := srv.setupMetrics(config.Telemetry, config.Name); err != nil {
+	if err := srv.setupMetrics(config.Telemetry, config.Identity); err != nil {
 		return nil, err
 	}
 
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 2e22095460..0d3aeb35c6 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -25,6 +25,8 @@ import (
 	"time"
 
 	"github.com/davecgh/go-spew/spew"
+	"github.com/tyler-smith/go-bip39"
+
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
@@ -47,7 +49,6 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc"
-	"github.com/tyler-smith/go-bip39"
 )
 
 // PublicEthereumAPI provides an API to access Ethereum related information.
@@ -829,10 +830,10 @@ func (s *PublicBlockChainAPI) getAuthor(head *types.Header) *common.Address {
 }
 
 // GetBlockByNumber returns the requested canonical block.
-// * When blockNr is -1 the chain head is returned.
-// * When blockNr is -2 the pending chain head is returned.
-// * When fullTx is true all transactions in the block are returned, otherwise
-//   only the transaction hash is returned.
+//   - When blockNr is -1 the chain head is returned.
+//   - When blockNr is -2 the pending chain head is returned.
+//   - When fullTx is true all transactions in the block are returned, otherwise
+//     only the transaction hash is returned.
 func (s *PublicBlockChainAPI) GetBlockByNumber(ctx context.Context, number rpc.BlockNumber, fullTx bool) (map[string]interface{}, error) {
 	block, err := s.b.BlockByNumber(ctx, number)
 	if block != nil && err == nil {
diff --git a/les/client.go b/les/client.go
index 87d4f00dad..58944658c9 100644
--- a/les/client.go
+++ b/les/client.go
@@ -30,6 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/bloombits"
 	"github.com/ethereum/go-ethereum/core/rawdb"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/eth/downloader/whitelist"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
 	"github.com/ethereum/go-ethereum/eth/filters"
 	"github.com/ethereum/go-ethereum/eth/gasprice"
@@ -145,7 +146,7 @@ func New(stack *node.Node, config *ethconfig.Config) (*LightEthereum, error) {
 	}
 	// Note: NewLightChain adds the trusted checkpoint so it needs an ODR with
 	// indexers already set but not started yet
-	if leth.blockchain, err = light.NewLightChain(leth.odr, leth.chainConfig, leth.engine, checkpoint); err != nil {
+	if leth.blockchain, err = light.NewLightChain(leth.odr, leth.chainConfig, leth.engine, checkpoint, whitelist.NewService(10)); err != nil {
 		return nil, err
 	}
 	leth.chainReader = leth.blockchain
diff --git a/les/test_helper.go b/les/test_helper.go
index 480d249dca..a099458353 100644
--- a/les/test_helper.go
+++ b/les/test_helper.go
@@ -203,7 +203,7 @@ func newTestClientHandler(backend *backends.SimulatedBackend, odr *LesOdr, index
 		oracle *checkpointoracle.CheckpointOracle
 	)
 	genesis := gspec.MustCommit(db)
-	chain, _ := light.NewLightChain(odr, gspec.Config, engine, nil)
+	chain, _ := light.NewLightChain(odr, gspec.Config, engine, nil, nil)
 	if indexers != nil {
 		checkpointConfig := &params.CheckpointOracleConfig{
 			Address:   crypto.CreateAddress(bankAddr, 0),
diff --git a/light/lightchain.go b/light/lightchain.go
index ee4146a2d8..98ffa216c6 100644
--- a/light/lightchain.go
+++ b/light/lightchain.go
@@ -26,6 +26,9 @@ import (
 	"sync/atomic"
 	"time"
 
+	lru "github.com/hashicorp/golang-lru"
+
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core"
@@ -37,7 +40,6 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
-	lru "github.com/hashicorp/golang-lru"
 )
 
 var (
@@ -81,7 +83,7 @@ type LightChain struct {
 // NewLightChain returns a fully initialised light chain using information
 // available in the database. It initialises the default Ethereum header
 // validator.
-func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.Engine, checkpoint *params.TrustedCheckpoint) (*LightChain, error) {
+func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.Engine, checkpoint *params.TrustedCheckpoint, checker ethereum.ChainValidator) (*LightChain, error) {
 	bodyCache, _ := lru.New(bodyCacheLimit)
 	bodyRLPCache, _ := lru.New(bodyCacheLimit)
 	blockCache, _ := lru.New(blockCacheLimit)
@@ -96,7 +98,7 @@ func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.
 		blockCache:    blockCache,
 		engine:        engine,
 	}
-	bc.forker = core.NewForkChoice(bc, nil)
+	bc.forker = core.NewForkChoice(bc, nil, checker)
 	var err error
 	bc.hc, err = core.NewHeaderChain(odr.Database(), config, bc.engine, bc.getProcInterrupt)
 	if err != nil {
diff --git a/light/lightchain_test.go b/light/lightchain_test.go
index 8600e56345..4747fc58c6 100644
--- a/light/lightchain_test.go
+++ b/light/lightchain_test.go
@@ -56,7 +56,7 @@ func newCanonical(n int) (ethdb.Database, *LightChain, error) {
 	db := rawdb.NewMemoryDatabase()
 	gspec := core.Genesis{Config: params.TestChainConfig}
 	genesis := gspec.MustCommit(db)
-	blockchain, _ := NewLightChain(&dummyOdr{db: db, indexerConfig: TestClientIndexerConfig}, gspec.Config, ethash.NewFaker(), nil)
+	blockchain, _ := NewLightChain(&dummyOdr{db: db, indexerConfig: TestClientIndexerConfig}, gspec.Config, ethash.NewFaker(), nil, nil)
 
 	// Create and inject the requested chain
 	if n == 0 {
@@ -76,7 +76,7 @@ func newTestLightChain() *LightChain {
 		Config:     params.TestChainConfig,
 	}
 	gspec.MustCommit(db)
-	lc, err := NewLightChain(&dummyOdr{db: db}, gspec.Config, ethash.NewFullFaker(), nil)
+	lc, err := NewLightChain(&dummyOdr{db: db}, gspec.Config, ethash.NewFullFaker(), nil, nil)
 	if err != nil {
 		panic(err)
 	}
@@ -347,7 +347,7 @@ func TestReorgBadHeaderHashes(t *testing.T) {
 	defer func() { delete(core.BadHashes, headers[3].Hash()) }()
 
 	// Create a new LightChain and check that it rolled back the state.
-	ncm, err := NewLightChain(&dummyOdr{db: bc.chainDb}, params.TestChainConfig, ethash.NewFaker(), nil)
+	ncm, err := NewLightChain(&dummyOdr{db: bc.chainDb}, params.TestChainConfig, ethash.NewFaker(), nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create new chain manager: %v", err)
 	}
diff --git a/light/odr_test.go b/light/odr_test.go
index fdf657a82e..9f4b42e675 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -261,14 +261,14 @@ func testChainOdr(t *testing.T, protocol int, fn odrTestFn) {
 	)
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
-	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		t.Fatal(err)
 	}
 
 	odr := &testOdr{sdb: sdb, ldb: ldb, indexerConfig: TestClientIndexerConfig}
-	lightchain, err := NewLightChain(odr, params.TestChainConfig, ethash.NewFullFaker(), nil)
+	lightchain, err := NewLightChain(odr, params.TestChainConfig, ethash.NewFullFaker(), nil, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/light/trie_test.go b/light/trie_test.go
index e8294cc2a2..24cf6ec48e 100644
--- a/light/trie_test.go
+++ b/light/trie_test.go
@@ -44,7 +44,8 @@ func TestNodeIterator(t *testing.T) {
 		genesis = gspec.MustCommit(fulldb)
 	)
 	gspec.MustCommit(lightdb)
-	blockchain, _ := core.NewBlockChain(fulldb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil)
+
+	blockchain, _ := core.NewBlockChain(fulldb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), fulldb, 4, testChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
diff --git a/light/txpool_test.go b/light/txpool_test.go
index cc2651d29a..a078a18f1a 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -91,7 +91,7 @@ func TestTxPool(t *testing.T) {
 	)
 	gspec.MustCommit(ldb)
 	// Assemble the test environment
-	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil)
+	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil, nil, nil)
 	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, poolTestBlocks, txPoolTestChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
@@ -103,7 +103,7 @@ func TestTxPool(t *testing.T) {
 		discard: make(chan int, 1),
 		mined:   make(chan int, 1),
 	}
-	lightchain, _ := NewLightChain(odr, params.TestChainConfig, ethash.NewFullFaker(), nil)
+	lightchain, _ := NewLightChain(odr, params.TestChainConfig, ethash.NewFullFaker(), nil, nil)
 	txPermanent = 50
 	pool := NewTxPool(params.TestChainConfig, lightchain, relay)
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
diff --git a/miner/fake_miner.go b/miner/fake_miner.go
index 43b397c428..c5c1fbd3b1 100644
--- a/miner/fake_miner.go
+++ b/miner/fake_miner.go
@@ -84,7 +84,7 @@ func createBorMiner(t *testing.T, ethAPIMock api.Caller, spanner bor.Spanner, he
 	engine := NewFakeBor(t, chainDB, chainConfig, ethAPIMock, spanner, heimdallClientMock, contractMock)
 
 	// Create Ethereum backend
-	bc, err := core.NewBlockChain(chainDB, nil, chainConfig, engine, vm.Config{}, nil, nil)
+	bc, err := core.NewBlockChain(chainDB, nil, chainConfig, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("can't create new chain %v", err)
 	}
diff --git a/miner/test_backend.go b/miner/test_backend.go
index d1d9d5b237..29da747ae0 100644
--- a/miner/test_backend.go
+++ b/miner/test_backend.go
@@ -91,7 +91,7 @@ func newTestWorkerBackend(t TensingObject, chainConfig *params.ChainConfig, engi
 
 	genesis := gspec.MustCommit(db)
 
-	chain, _ := core.NewBlockChain(db, &core.CacheConfig{TrieDirtyDisabled: true}, gspec.Config, engine, vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db, &core.CacheConfig{TrieDirtyDisabled: true}, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	txpool := core.NewTxPool(testTxPoolConfig, chainConfig, chain)
 
 	// Generate a small n-block chain and an uncle block for it
diff --git a/miner/worker_test.go b/miner/worker_test.go
index 9bb2a538ce..011895c854 100644
--- a/miner/worker_test.go
+++ b/miner/worker_test.go
@@ -114,7 +114,7 @@ func testGenerateBlockAndImport(t *testing.T, isClique bool, isBor bool) {
 	db2 := rawdb.NewMemoryDatabase()
 	b.Genesis.MustCommit(db2)
 
-	chain, _ := core.NewBlockChain(db2, nil, b.chain.Config(), engine, vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db2, nil, b.chain.Config(), engine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	// Ignore empty commit here for less noise.
@@ -650,7 +650,7 @@ func BenchmarkBorMining(b *testing.B) {
 	db2 := rawdb.NewMemoryDatabase()
 	back.Genesis.MustCommit(db2)
 
-	chain, _ := core.NewBlockChain(db2, nil, back.chain.Config(), engine, vm.Config{}, nil, nil)
+	chain, _ := core.NewBlockChain(db2, nil, back.chain.Config(), engine, vm.Config{}, nil, nil, nil)
 	defer chain.Stop()
 
 	// Ignore empty commit here for less noise.
diff --git a/tests/block_test_util.go b/tests/block_test_util.go
index d28f3a1237..487fd2d4d8 100644
--- a/tests/block_test_util.go
+++ b/tests/block_test_util.go
@@ -128,7 +128,8 @@ func (t *BlockTest) Run(snapshotter bool) error {
 		cache.SnapshotLimit = 1
 		cache.SnapshotWait = true
 	}
-	chain, err := core.NewBlockChain(db, cache, config, engine, vm.Config{}, nil, nil)
+
+	chain, err := core.NewBlockChain(db, cache, config, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		return err
 	}
diff --git a/tests/bor/bor_api_test.go b/tests/bor/bor_api_test.go
new file mode 100644
index 0000000000..fc81480902
--- /dev/null
+++ b/tests/bor/bor_api_test.go
@@ -0,0 +1,168 @@
+//go:build integration
+
+package bor
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/require"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/bor"
+	"github.com/ethereum/go-ethereum/consensus/bor/clerk"
+	"github.com/ethereum/go-ethereum/consensus/bor/heimdall/checkpoint"
+	"github.com/ethereum/go-ethereum/consensus/bor/valset"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/internal/ethapi"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/ethereum/go-ethereum/tests/bor/mocks"
+)
+
+func TestGetTransactionReceiptsByBlock(t *testing.T) {
+	init := buildEthereumInstance(t, rawdb.NewMemoryDatabase())
+	chain := init.ethereum.BlockChain()
+	engine := init.ethereum.Engine()
+
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	_bor := engine.(*bor.Bor)
+	defer _bor.Close()
+
+	// Mock /bor/span/1
+	res, _ := loadSpanFromFile(t)
+
+	h := mocks.NewMockIHeimdallClient(ctrl)
+
+	h.EXPECT().Span(gomock.Any(), uint64(1)).Return(&res.Result, nil).MinTimes(1)
+	h.EXPECT().Close().MinTimes(1)
+	h.EXPECT().FetchCheckpoint(gomock.Any(), int64(-1)).Return(&checkpoint.Checkpoint{
+		Proposer:   res.Result.SelectedProducers[0].Address,
+		StartBlock: big.NewInt(0),
+		EndBlock:   big.NewInt(int64(spanSize)),
+	}, nil).AnyTimes()
+
+	// Mock State Sync events
+	// at # sprintSize, events are fetched for [fromID, (block-sprint).Time)
+	fromID := uint64(1)
+	to := int64(chain.GetHeaderByNumber(0).Time)
+	sample := getSampleEventRecord(t)
+
+	// First query will be from [id=1, (block-sprint).Time]
+	eventRecords := []*clerk.EventRecordWithTime{
+		buildStateEvent(sample, 1, 1),
+		buildStateEvent(sample, 2, 2),
+		buildStateEvent(sample, 3, 3),
+	}
+
+	h.EXPECT().StateSyncEvents(gomock.Any(), fromID, to).Return(eventRecords, nil).MinTimes(1)
+	_bor.SetHeimdallClient(h)
+
+	// Insert blocks for 0th sprint
+	db := init.ethereum.ChainDb()
+	block := init.genesis.ToBlock(db)
+
+	signer := types.LatestSigner(init.genesis.Config)
+	toAddress := common.HexToAddress("0x000000000000000000000000000000000000aaaa")
+
+	currentValidators := []*valset.Validator{valset.NewValidator(addr, 10)}
+	txHashes := map[int]common.Hash{} // blockNumber -> txHash
+
+	var (
+		err   error
+		nonce uint64
+		tx    *types.Transaction
+		txs   []*types.Transaction
+	)
+
+	for i := uint64(1); i <= sprintSize; i++ {
+		if IsSpanEnd(i) {
+			currentValidators = []*valset.Validator{valset.NewValidator(addr, 10)}
+		}
+
+		if i%3 == 0 {
+			txdata := &types.LegacyTx{
+				Nonce:    nonce,
+				To:       &toAddress,
+				Gas:      30000,
+				GasPrice: newGwei(5),
+			}
+
+			nonce++
+
+			tx = types.NewTx(txdata)
+			tx, err = types.SignTx(tx, signer, key)
+			require.Nil(t, err, "an incorrect transaction or signer")
+
+			txs = []*types.Transaction{tx}
+		} else {
+			txs = nil
+		}
+
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, txs, currentValidators)
+		insertNewBlock(t, chain, block)
+
+		if len(txs) != 0 {
+			txHashes[int(block.Number().Uint64())] = tx.Hash()
+		}
+	}
+
+	// state 6 was not written
+	//
+	fromID = uint64(4)
+	to = int64(chain.GetHeaderByNumber(sprintSize).Time)
+
+	eventRecords = []*clerk.EventRecordWithTime{
+		buildStateEvent(sample, 4, 4),
+		buildStateEvent(sample, 5, 5),
+	}
+	h.EXPECT().StateSyncEvents(gomock.Any(), fromID, to).Return(eventRecords, nil).MinTimes(1)
+
+	for i := sprintSize + 1; i <= spanSize; i++ {
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, currentValidators)
+		insertNewBlock(t, chain, block)
+	}
+
+	ethAPI := ethapi.NewPublicBlockChainAPI(init.ethereum.APIBackend)
+	txPoolAPI := ethapi.NewPublicTransactionPoolAPI(init.ethereum.APIBackend, nil)
+
+	for n := 0; n < int(spanSize)+1; n++ {
+		rpcNumber := rpc.BlockNumberOrHashWithNumber(rpc.BlockNumber(n))
+
+		txs, err := ethAPI.GetTransactionReceiptsByBlock(context.Background(), rpcNumber)
+		require.Nil(t, err)
+
+		tx := txPoolAPI.GetTransactionByBlockNumberAndIndex(context.Background(), rpc.BlockNumber(n), 0)
+
+		blockMap, err := ethAPI.GetBlockByNumber(context.Background(), rpc.BlockNumber(n), true)
+		require.Nil(t, err)
+
+		expectedTxHash, ok := txHashes[n]
+		// FIXME: add `IsSprintStart(uint64(n)) || IsSpanStart(uint64(n))` after adding a full state receiver contract
+		if ok {
+			require.Len(t, txs, 1)
+
+			require.NotNil(t, tx, "not nil receipt expected")
+
+			require.Equal(t, expectedTxHash, tx.Hash, "got different from expected receipt")
+
+			blockTxs, ok := blockMap["transactions"].([]interface{})
+			require.Len(t, blockTxs, 1)
+
+			blockTx, ok := blockTxs[0].(*ethapi.RPCTransaction)
+			require.True(t, ok)
+			require.Equal(t, expectedTxHash, blockTx.Hash)
+		} else {
+			require.Len(t, txs, 0)
+
+			require.Nil(t, tx, "nil receipt expected")
+
+			blockTxs, _ := blockMap["transactions"].([]interface{})
+			require.Len(t, blockTxs, 0)
+		}
+	}
+}
diff --git a/tests/bor/bor_test.go b/tests/bor/bor_test.go
index d179c6ea9b..646a38604d 100644
--- a/tests/bor/bor_test.go
+++ b/tests/bor/bor_test.go
@@ -11,14 +11,15 @@ import (
 	"time"
 
 	"github.com/golang/mock/gomock"
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"golang.org/x/crypto/sha3"
 
+	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus/bor"
 	"github.com/ethereum/go-ethereum/consensus/bor/clerk"
 	"github.com/ethereum/go-ethereum/consensus/bor/heimdall/checkpoint"
-	"github.com/ethereum/go-ethereum/consensus/bor/heimdall/span"
+	"github.com/ethereum/go-ethereum/consensus/bor/valset"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/rawdb"
@@ -38,13 +39,13 @@ func TestInsertingSpanSizeBlocks(t *testing.T) {
 
 	defer _bor.Close()
 
-	h, heimdallSpan, ctrl := getMockedHeimdallClient(t)
-	defer ctrl.Finish()
-
 	_, currentSpan := loadSpanFromFile(t)
 
+	h, ctrl := getMockedHeimdallClient(t, currentSpan)
+	defer ctrl.Finish()
+
 	h.EXPECT().Close().AnyTimes()
-	h.EXPECT().FetchLatestCheckpoint(gomock.Any()).Return(&checkpoint.Checkpoint{
+	h.EXPECT().FetchCheckpoint(gomock.Any(), int64(-1)).Return(&checkpoint.Checkpoint{
 		Proposer:   currentSpan.SelectedProducers[0].Address,
 		StartBlock: big.NewInt(0),
 		EndBlock:   big.NewInt(int64(spanSize)),
@@ -56,9 +57,11 @@ func TestInsertingSpanSizeBlocks(t *testing.T) {
 	block := init.genesis.ToBlock(db)
 	// to := int64(block.Header().Time)
 
+	currentValidators := []*valset.Validator{valset.NewValidator(addr, 10)}
+
 	// Insert sprintSize # of blocks so that span is fetched at the start of a new sprint
 	for i := uint64(1); i <= spanSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, currentValidators)
 		insertNewBlock(t, chain, block)
 	}
 
@@ -67,10 +70,10 @@ func TestInsertingSpanSizeBlocks(t *testing.T) {
 		t.Fatalf("%s", err)
 	}
 
-	assert.Equal(t, 3, len(validators))
+	require.Equal(t, 3, len(validators))
 	for i, validator := range validators {
-		assert.Equal(t, validator.Address.Bytes(), heimdallSpan.SelectedProducers[i].Address.Bytes())
-		assert.Equal(t, validator.VotingPower, heimdallSpan.SelectedProducers[i].VotingPower)
+		require.Equal(t, validator.Address.Bytes(), currentSpan.SelectedProducers[i].Address.Bytes())
+		require.Equal(t, validator.VotingPower, currentSpan.SelectedProducers[i].VotingPower)
 	}
 }
 
@@ -85,16 +88,23 @@ func TestFetchStateSyncEvents(t *testing.T) {
 	// A. Insert blocks for 0th sprint
 	db := init.ethereum.ChainDb()
 	block := init.genesis.ToBlock(db)
+
+	// B.1 Mock /bor/span/1
+	res, _ := loadSpanFromFile(t)
+
+	currentValidators := []*valset.Validator{valset.NewValidator(addr, 10)}
+
 	// Insert sprintSize # of blocks so that span is fetched at the start of a new sprint
 	for i := uint64(1); i < sprintSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		if IsSpanEnd(i) {
+			currentValidators = res.Result.ValidatorSet.Validators
+		}
+
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, currentValidators)
 		insertNewBlock(t, chain, block)
 	}
 
 	// B. Before inserting 1st block of the next sprint, mock heimdall deps
-	// B.1 Mock /bor/span/1
-	res, _ := loadSpanFromFile(t)
-
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 
@@ -115,7 +125,7 @@ func TestFetchStateSyncEvents(t *testing.T) {
 	h.EXPECT().StateSyncEvents(gomock.Any(), fromID, to).Return(eventRecords, nil).AnyTimes()
 	_bor.SetHeimdallClient(h)
 
-	block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+	block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, res.Result.ValidatorSet.Validators)
 	insertNewBlock(t, chain, block)
 }
 
@@ -130,6 +140,9 @@ func TestFetchStateSyncEvents_2(t *testing.T) {
 	// Mock /bor/span/1
 	res, _ := loadSpanFromFile(t)
 
+	// add the block producer
+	res.Result.ValidatorSet.Validators = append(res.Result.ValidatorSet.Validators, valset.NewValidator(addr, 4500))
+
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 
@@ -160,15 +173,24 @@ func TestFetchStateSyncEvents_2(t *testing.T) {
 	// Insert blocks for 0th sprint
 	db := init.ethereum.ChainDb()
 	block := init.genesis.ToBlock(db)
+
+	var currentValidators []*valset.Validator
+
 	for i := uint64(1); i <= sprintSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		if IsSpanEnd(i) {
+			currentValidators = res.Result.ValidatorSet.Validators
+		} else {
+			currentValidators = []*valset.Validator{valset.NewValidator(addr, 10)}
+		}
+
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, currentValidators)
 		insertNewBlock(t, chain, block)
 	}
 
 	lastStateID, _ := _bor.GenesisContractsClient.LastStateId(sprintSize)
 
 	// state 6 was not written
-	assert.Equal(t, uint64(4), lastStateID.Uint64())
+	require.Equal(t, uint64(4), lastStateID.Uint64())
 
 	//
 	fromID = uint64(5)
@@ -181,12 +203,18 @@ func TestFetchStateSyncEvents_2(t *testing.T) {
 	h.EXPECT().StateSyncEvents(gomock.Any(), fromID, to).Return(eventRecords, nil).AnyTimes()
 
 	for i := sprintSize + 1; i <= spanSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		if IsSpanEnd(i) {
+			currentValidators = res.Result.ValidatorSet.Validators
+		} else {
+			currentValidators = []*valset.Validator{valset.NewValidator(addr, 10)}
+		}
+
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, res.Result.ValidatorSet.Validators)
 		insertNewBlock(t, chain, block)
 	}
 
 	lastStateID, _ = _bor.GenesisContractsClient.LastStateId(spanSize)
-	assert.Equal(t, uint64(6), lastStateID.Uint64())
+	require.Equal(t, uint64(6), lastStateID.Uint64())
 }
 
 func TestOutOfTurnSigning(t *testing.T) {
@@ -197,17 +225,29 @@ func TestOutOfTurnSigning(t *testing.T) {
 
 	defer _bor.Close()
 
-	h, _, ctrl := getMockedHeimdallClient(t)
+	_, heimdallSpan := loadSpanFromFile(t)
+	proposer := valset.NewValidator(addr, 10)
+	heimdallSpan.ValidatorSet.Validators = append(heimdallSpan.ValidatorSet.Validators, proposer)
+
+	// add the block producer
+	h, ctrl := getMockedHeimdallClient(t, heimdallSpan)
 	defer ctrl.Finish()
 
 	h.EXPECT().Close().AnyTimes()
+
 	_bor.SetHeimdallClient(h)
 
 	db := init.ethereum.ChainDb()
 	block := init.genesis.ToBlock(db)
 
+	setDifficulty := func(header *types.Header) {
+		if IsSprintStart(header.Number.Uint64()) {
+			header.Difficulty = big.NewInt(int64(len(heimdallSpan.ValidatorSet.Validators)))
+		}
+	}
+
 	for i := uint64(1); i < spanSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, heimdallSpan.ValidatorSet.Validators, setDifficulty)
 		insertNewBlock(t, chain, block)
 	}
 
@@ -215,36 +255,50 @@ func TestOutOfTurnSigning(t *testing.T) {
 	// This account is one the out-of-turn validators for 1st (0-indexed) span
 	signer := "c8deb0bea5c41afe8e37b4d1bd84e31adff11b09c8c96ff4b605003cce067cd9"
 	signerKey, _ := hex.DecodeString(signer)
-	key, _ = crypto.HexToECDSA(signer)
-	addr = crypto.PubkeyToAddress(key.PublicKey)
+	newKey, _ := crypto.HexToECDSA(signer)
+	newAddr := crypto.PubkeyToAddress(newKey.PublicKey)
 	expectedSuccessionNumber := 2
 
-	block = buildNextBlock(t, _bor, chain, block, signerKey, init.genesis.Config.Bor)
-	_, err := chain.InsertChain([]*types.Block{block})
-	assert.Equal(t,
-		*err.(*bor.BlockTooSoonError),
-		bor.BlockTooSoonError{Number: spanSize, Succession: expectedSuccessionNumber})
+	parentTime := block.Time()
 
-	expectedDifficulty := uint64(3 - expectedSuccessionNumber) // len(validators) - succession
+	setParentTime := func(header *types.Header) {
+		header.Time = parentTime + 1
+	}
+
+	const turn = 1
+
+	setDifficulty = func(header *types.Header) {
+		header.Difficulty = big.NewInt(int64(len(heimdallSpan.ValidatorSet.Validators)) - turn)
+	}
+
+	block = buildNextBlock(t, _bor, chain, block, signerKey, init.genesis.Config.Bor, nil, heimdallSpan.ValidatorSet.Validators, setParentTime, setDifficulty)
+	_, err := chain.InsertChain([]*types.Block{block})
+	require.Equal(t,
+		bor.BlockTooSoonError{Number: spanSize, Succession: expectedSuccessionNumber},
+		*err.(*bor.BlockTooSoonError))
+
+	expectedDifficulty := uint64(len(heimdallSpan.ValidatorSet.Validators) - expectedSuccessionNumber - turn) // len(validators) - succession
 	header := block.Header()
 
-	header.Time += bor.CalcProducerDelay(header.Number.Uint64(), expectedSuccessionNumber, init.genesis.Config.Bor) -
-		bor.CalcProducerDelay(header.Number.Uint64(), 0, init.genesis.Config.Bor)
+	diff := bor.CalcProducerDelay(header.Number.Uint64(), expectedSuccessionNumber, init.genesis.Config.Bor)
+	header.Time += diff
 
 	sign(t, header, signerKey, init.genesis.Config.Bor)
+
 	block = types.NewBlockWithHeader(header)
 
 	_, err = chain.InsertChain([]*types.Block{block})
-	assert.Equal(t,
-		*err.(*bor.WrongDifficultyError),
-		bor.WrongDifficultyError{Number: spanSize, Expected: expectedDifficulty, Actual: 3, Signer: addr.Bytes()})
+	require.NotNil(t, err)
+	require.Equal(t,
+		bor.WrongDifficultyError{Number: spanSize, Expected: expectedDifficulty, Actual: 3, Signer: newAddr.Bytes()},
+		*err.(*bor.WrongDifficultyError))
 
 	header.Difficulty = new(big.Int).SetUint64(expectedDifficulty)
 	sign(t, header, signerKey, init.genesis.Config.Bor)
 	block = types.NewBlockWithHeader(header)
 
 	_, err = chain.InsertChain([]*types.Block{block})
-	assert.Nil(t, err)
+	require.Nil(t, err)
 }
 
 func TestSignerNotFound(t *testing.T) {
@@ -255,7 +309,9 @@ func TestSignerNotFound(t *testing.T) {
 
 	defer _bor.Close()
 
-	h, _, ctrl := getMockedHeimdallClient(t)
+	_, heimdallSpan := loadSpanFromFile(t)
+
+	h, ctrl := getMockedHeimdallClient(t, heimdallSpan)
 	defer ctrl.Finish()
 
 	h.EXPECT().Close().AnyTimes()
@@ -266,62 +322,21 @@ func TestSignerNotFound(t *testing.T) {
 	block := init.genesis.ToBlock(db)
 
 	// random signer account that is not a part of the validator set
-	signer := "3714d99058cd64541433d59c6b391555b2fd9b54629c2b717a6c9c00d1127b6b"
+	const signer = "3714d99058cd64541433d59c6b391555b2fd9b54629c2b717a6c9c00d1127b6b"
 	signerKey, _ := hex.DecodeString(signer)
-	key, _ = crypto.HexToECDSA(signer)
-	addr = crypto.PubkeyToAddress(key.PublicKey)
+	newKey, _ := crypto.HexToECDSA(signer)
+	newAddr := crypto.PubkeyToAddress(newKey.PublicKey)
+
+	_bor.Authorize(newAddr, func(account accounts.Account, s string, data []byte) ([]byte, error) {
+		return crypto.Sign(crypto.Keccak256(data), newKey)
+	})
+
+	block = buildNextBlock(t, _bor, chain, block, signerKey, init.genesis.Config.Bor, nil, heimdallSpan.ValidatorSet.Validators)
 
-	block = buildNextBlock(t, _bor, chain, block, signerKey, init.genesis.Config.Bor)
 	_, err := chain.InsertChain([]*types.Block{block})
-	assert.Equal(t,
+	require.Equal(t,
 		*err.(*bor.UnauthorizedSignerError),
-		bor.UnauthorizedSignerError{Number: 0, Signer: addr.Bytes()})
-}
-
-func getMockedHeimdallClient(t *testing.T) (*mocks.MockIHeimdallClient, *span.HeimdallSpan, *gomock.Controller) {
-	ctrl := gomock.NewController(t)
-	h := mocks.NewMockIHeimdallClient(ctrl)
-
-	_, heimdallSpan := loadSpanFromFile(t)
-
-	h.EXPECT().Span(gomock.Any(), uint64(1)).Return(heimdallSpan, nil).AnyTimes()
-
-	h.EXPECT().StateSyncEvents(gomock.Any(), gomock.Any(), gomock.Any()).
-		Return([]*clerk.EventRecordWithTime{getSampleEventRecord(t)}, nil).AnyTimes()
-
-	return h, heimdallSpan, ctrl
-}
-
-func generateFakeStateSyncEvents(sample *clerk.EventRecordWithTime, count int) []*clerk.EventRecordWithTime {
-	events := make([]*clerk.EventRecordWithTime, count)
-	event := *sample
-	event.ID = 1
-	events[0] = &clerk.EventRecordWithTime{}
-	*events[0] = event
-	for i := 1; i < count; i++ {
-		event.ID = uint64(i)
-		event.Time = event.Time.Add(1 * time.Second)
-		events[i] = &clerk.EventRecordWithTime{}
-		*events[i] = event
-	}
-	return events
-}
-
-func buildStateEvent(sample *clerk.EventRecordWithTime, id uint64, timeStamp int64) *clerk.EventRecordWithTime {
-	event := *sample
-	event.ID = id
-	event.Time = time.Unix(timeStamp, 0)
-	return &event
-}
-
-func getSampleEventRecord(t *testing.T) *clerk.EventRecordWithTime {
-	eventRecords := stateSyncEventsPayload(t)
-	eventRecords.Result[0].Time = time.Unix(1, 0)
-	return eventRecords.Result[0]
-}
-
-func getEventRecords(t *testing.T) []*clerk.EventRecordWithTime {
-	return stateSyncEventsPayload(t).Result
+		bor.UnauthorizedSignerError{Number: 0, Signer: newAddr.Bytes()})
 }
 
 // TestEIP1559Transition tests the following:
@@ -351,7 +366,7 @@ func TestEIP1559Transition(t *testing.T) {
 		addr3 = crypto.PubkeyToAddress(key3.PublicKey)
 		funds = new(big.Int).Mul(common.Big1, big.NewInt(params.Ether))
 		gspec = &core.Genesis{
-			Config: params.BorTestChainConfig,
+			Config: params.BorUnittestChainConfig,
 			Alloc: core.GenesisAlloc{
 				addr1: {Balance: funds},
 				addr2: {Balance: funds},
@@ -403,7 +418,7 @@ func TestEIP1559Transition(t *testing.T) {
 	diskdb := rawdb.NewMemoryDatabase()
 	gspec.MustCommit(diskdb)
 
-	chain, err := core.NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil)
+	chain, err := core.NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil, nil)
 	if err != nil {
 		t.Fatalf("failed to create tester chain: %v", err)
 	}
@@ -433,7 +448,7 @@ func TestEIP1559Transition(t *testing.T) {
 	}
 
 	// check burnt contract balance
-	actual = state.GetBalance(common.HexToAddress(params.BorTestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
+	actual = state.GetBalance(common.HexToAddress(params.BorUnittestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
 	expected = new(big.Int).Mul(new(big.Int).SetUint64(block.GasUsed()), block.BaseFee())
 	burntContractBalance := expected
 	if actual.Cmp(expected) != 0 {
@@ -481,7 +496,7 @@ func TestEIP1559Transition(t *testing.T) {
 	}
 
 	// check burnt contract balance
-	actual = state.GetBalance(common.HexToAddress(params.BorTestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
+	actual = state.GetBalance(common.HexToAddress(params.BorUnittestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
 	expected = new(big.Int).Add(burntContractBalance, new(big.Int).Mul(new(big.Int).SetUint64(block.GasUsed()), block.BaseFee()))
 	burntContractBalance = expected
 	if actual.Cmp(expected) != 0 {
@@ -539,7 +554,7 @@ func TestEIP1559Transition(t *testing.T) {
 	state, _ = chain.State()
 
 	// check burnt contract balance
-	actual = state.GetBalance(common.HexToAddress(params.BorTestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
+	actual = state.GetBalance(common.HexToAddress(params.BorUnittestChainConfig.Bor.CalculateBurntContract(block.NumberU64())))
 	burntAmount := new(big.Int).Mul(
 		block.BaseFee(),
 		big.NewInt(int64(block.GasUsed())),
@@ -550,25 +565,188 @@ func TestEIP1559Transition(t *testing.T) {
 	}
 }
 
-func newGwei(n int64) *big.Int {
-	return new(big.Int).Mul(big.NewInt(n), big.NewInt(params.GWei))
+// EIP1559 is not supported without EIP155. An error is expected
+func TestEIP1559TransitionWithEIP155(t *testing.T) {
+	var (
+		aa = common.HexToAddress("0x000000000000000000000000000000000000aaaa")
+
+		// Generate a canonical chain to act as the main dataset
+		db     = rawdb.NewMemoryDatabase()
+		engine = ethash.NewFaker()
+
+		// A sender who makes transactions, has some funds
+		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
+		key3, _ = crypto.HexToECDSA("225171aed3793cba1c029832886d69785b7e77a54a44211226b447aa2d16b058")
+
+		addr1 = crypto.PubkeyToAddress(key1.PublicKey)
+		addr2 = crypto.PubkeyToAddress(key2.PublicKey)
+		addr3 = crypto.PubkeyToAddress(key3.PublicKey)
+		funds = new(big.Int).Mul(common.Big1, big.NewInt(params.Ether))
+		gspec = &core.Genesis{
+			Config: params.BorUnittestChainConfig,
+			Alloc: core.GenesisAlloc{
+				addr1: {Balance: funds},
+				addr2: {Balance: funds},
+				addr3: {Balance: funds},
+				// The address 0xAAAA sloads 0x00 and 0x01
+				aa: {
+					Code: []byte{
+						byte(vm.PC),
+						byte(vm.PC),
+						byte(vm.SLOAD),
+						byte(vm.SLOAD),
+					},
+					Nonce:   0,
+					Balance: big.NewInt(0),
+				},
+			},
+		}
+	)
+
+	genesis := gspec.MustCommit(db)
+
+	// Use signer without chain ID
+	signer := types.HomesteadSigner{}
+
+	_, _ = core.GenerateChain(gspec.Config, genesis, engine, db, 1, func(i int, b *core.BlockGen) {
+		b.SetCoinbase(common.Address{1})
+		// One transaction to 0xAAAA
+		accesses := types.AccessList{types.AccessTuple{
+			Address:     aa,
+			StorageKeys: []common.Hash{{0}},
+		}}
+
+		txdata := &types.DynamicFeeTx{
+			ChainID:    gspec.Config.ChainID,
+			Nonce:      0,
+			To:         &aa,
+			Gas:        30000,
+			GasFeeCap:  newGwei(5),
+			GasTipCap:  big.NewInt(2),
+			AccessList: accesses,
+			Data:       []byte{},
+		}
+
+		var err error
+
+		tx := types.NewTx(txdata)
+		tx, err = types.SignTx(tx, signer, key1)
+
+		require.ErrorIs(t, err, types.ErrTxTypeNotSupported)
+	})
+}
+
+// it is up to a user to use protected transactions. so if a transaction is unprotected no errors related to chainID are expected.
+// transactions are checked in 2 places: transaction pool and blockchain processor.
+func TestTransitionWithoutEIP155(t *testing.T) {
+	var (
+		aa = common.HexToAddress("0x000000000000000000000000000000000000aaaa")
+
+		// Generate a canonical chain to act as the main dataset
+		db     = rawdb.NewMemoryDatabase()
+		engine = ethash.NewFaker()
+
+		// A sender who makes transactions, has some funds
+		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+		key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
+		key3, _ = crypto.HexToECDSA("225171aed3793cba1c029832886d69785b7e77a54a44211226b447aa2d16b058")
+
+		addr1 = crypto.PubkeyToAddress(key1.PublicKey)
+		addr2 = crypto.PubkeyToAddress(key2.PublicKey)
+		addr3 = crypto.PubkeyToAddress(key3.PublicKey)
+		funds = new(big.Int).Mul(common.Big1, big.NewInt(params.Ether))
+		gspec = &core.Genesis{
+			Config: params.BorUnittestChainConfig,
+			Alloc: core.GenesisAlloc{
+				addr1: {Balance: funds},
+				addr2: {Balance: funds},
+				addr3: {Balance: funds},
+				// The address 0xAAAA sloads 0x00 and 0x01
+				aa: {
+					Code: []byte{
+						byte(vm.PC),
+						byte(vm.PC),
+						byte(vm.SLOAD),
+						byte(vm.SLOAD),
+					},
+					Nonce:   0,
+					Balance: big.NewInt(0),
+				},
+			},
+		}
+	)
+
+	genesis := gspec.MustCommit(db)
+
+	// Use signer without chain ID
+	signer := types.HomesteadSigner{}
+	//signer := types.FrontierSigner{}
+
+	blocks, _ := core.GenerateChain(gspec.Config, genesis, engine, db, 1, func(i int, b *core.BlockGen) {
+		b.SetCoinbase(common.Address{1})
+
+		txdata := &types.LegacyTx{
+			Nonce:    0,
+			To:       &aa,
+			Gas:      30000,
+			GasPrice: newGwei(5),
+		}
+
+		var err error
+
+		tx := types.NewTx(txdata)
+		tx, err = types.SignTx(tx, signer, key1)
+
+		require.Nil(t, err)
+		require.False(t, tx.Protected())
+
+		from, err := types.Sender(types.EIP155Signer{}, tx)
+		require.Equal(t, addr1, from)
+		require.Nil(t, err)
+
+		b.AddTx(tx)
+	})
+
+	diskdb := rawdb.NewMemoryDatabase()
+	gspec.MustCommit(diskdb)
+
+	chain, err := core.NewBlockChain(diskdb, nil, gspec.Config, engine, vm.Config{}, nil, nil, nil)
+	if err != nil {
+		t.Fatalf("failed to create tester chain: %v", err)
+	}
+	if n, err := chain.InsertChain(blocks); err != nil {
+		t.Fatalf("block %d: failed to insert into chain: %v", n, err)
+	}
+
+	block := chain.GetBlockByNumber(1)
+
+	require.Len(t, block.Transactions(), 1)
 }
 
 func TestJaipurFork(t *testing.T) {
 	init := buildEthereumInstance(t, rawdb.NewMemoryDatabase())
 	chain := init.ethereum.BlockChain()
 	engine := init.ethereum.Engine()
+
 	_bor := engine.(*bor.Bor)
+	defer _bor.Close()
+
 	db := init.ethereum.ChainDb()
 	block := init.genesis.ToBlock(db)
+
+	res, _ := loadSpanFromFile(t)
+
 	for i := uint64(1); i < sprintSize; i++ {
-		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor)
+		block = buildNextBlock(t, _bor, chain, block, nil, init.genesis.Config.Bor, nil, res.Result.ValidatorSet.Validators)
 		insertNewBlock(t, chain, block)
+
 		if block.Number().Uint64() == init.genesis.Config.Bor.JaipurBlock-1 {
-			assert.Equal(t, testSealHash(block.Header(), init.genesis.Config.Bor), bor.SealHash(block.Header(), init.genesis.Config.Bor))
+			require.Equal(t, testSealHash(block.Header(), init.genesis.Config.Bor), bor.SealHash(block.Header(), init.genesis.Config.Bor))
 		}
+
 		if block.Number().Uint64() == init.genesis.Config.Bor.JaipurBlock {
-			assert.Equal(t, testSealHash(block.Header(), init.genesis.Config.Bor), bor.SealHash(block.Header(), init.genesis.Config.Bor))
+			require.Equal(t, testSealHash(block.Header(), init.genesis.Config.Bor), bor.SealHash(block.Header(), init.genesis.Config.Bor))
 		}
 	}
 }
diff --git a/tests/bor/helper.go b/tests/bor/helper.go
index a8a3ae4ea6..f5d80bbebf 100644
--- a/tests/bor/helper.go
+++ b/tests/bor/helper.go
@@ -1,46 +1,63 @@
+//go:build integration
+
 package bor
 
 import (
 	"encoding/hex"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"math/big"
 	"sort"
 	"testing"
+	"time"
 
+	"github.com/golang/mock/gomock"
+
+	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/bor"
-	"github.com/ethereum/go-ethereum/consensus/bor/heimdall"
+	"github.com/ethereum/go-ethereum/consensus/bor/clerk"
+	"github.com/ethereum/go-ethereum/consensus/bor/heimdall" //nolint:typecheck
 	"github.com/ethereum/go-ethereum/consensus/bor/heimdall/span"
 	"github.com/ethereum/go-ethereum/consensus/bor/valset"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/secp256k1"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/tests/bor/mocks"
 )
 
 var (
+
+	// Only this account is a validator for the 0th span
+	key, _ = crypto.HexToECDSA(privKey)
+	addr   = crypto.PubkeyToAddress(key.PublicKey) // 0x71562b71999873DB5b286dF957af199Ec94617F7
+
+	// This account is one the validators for 1st span (0-indexed)
+	key2, _ = crypto.HexToECDSA(privKey2)
+	addr2   = crypto.PubkeyToAddress(key2.PublicKey) // 0x9fB29AAc15b9A4B7F17c3385939b007540f4d791
+)
+
+const (
+	privKey  = "b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291"
+	privKey2 = "9b28f36fbd67381120752d6172ecdcf10e06ab2d9a1367aac00cdcd6ac7855d3"
+
 	// The genesis for tests was generated with following parameters
 	extraSeal = 65 // Fixed number of extra-data suffix bytes reserved for signer seal
 
-	// Only this account is a validator for the 0th span
-	privKey = "b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291"
-	key, _  = crypto.HexToECDSA(privKey)
-	addr    = crypto.PubkeyToAddress(key.PublicKey) // 0x71562b71999873DB5b286dF957af199Ec94617F7
+	sprintSize uint64 = 4
+	spanSize   uint64 = 8
 
-	// This account is one the validators for 1st span (0-indexed)
-	privKey2 = "9b28f36fbd67381120752d6172ecdcf10e06ab2d9a1367aac00cdcd6ac7855d3"
-	key2, _  = crypto.HexToECDSA(privKey2)
-	addr2    = crypto.PubkeyToAddress(key2.PublicKey) // 0x9fB29AAc15b9A4B7F17c3385939b007540f4d791
-
-	validatorHeaderBytesLength        = common.AddressLength + 20 // address + power
-	sprintSize                 uint64 = 4
-	spanSize                   uint64 = 8
+	validatorHeaderBytesLength = common.AddressLength + 20 // address + power
 )
 
 type initializeData struct {
@@ -49,8 +66,6 @@ type initializeData struct {
 }
 
 func buildEthereumInstance(t *testing.T, db ethdb.Database) *initializeData {
-	t.Helper()
-
 	genesisData, err := ioutil.ReadFile("./testdata/genesis.json")
 	if err != nil {
 		t.Fatalf("%s", err)
@@ -64,6 +79,7 @@ func buildEthereumInstance(t *testing.T, db ethdb.Database) *initializeData {
 
 	ethConf := &eth.Config{
 		Genesis: gen,
+		BorLogs: true,
 	}
 
 	ethConf.Genesis.MustCommit(db)
@@ -75,6 +91,10 @@ func buildEthereumInstance(t *testing.T, db ethdb.Database) *initializeData {
 
 	ethConf.Genesis.MustCommit(ethereum.ChainDb())
 
+	ethereum.Engine().(*bor.Bor).Authorize(addr, func(account accounts.Account, s string, data []byte) ([]byte, error) {
+		return crypto.Sign(crypto.Keccak256(data), key)
+	})
+
 	return &initializeData{
 		genesis:  gen,
 		ethereum: ethereum,
@@ -89,33 +109,31 @@ func insertNewBlock(t *testing.T, chain *core.BlockChain, block *types.Block) {
 	}
 }
 
-func buildNextBlock(t *testing.T, _bor *bor.Bor, chain *core.BlockChain, block *types.Block, signer []byte, borConfig *params.BorConfig) *types.Block {
+type Option func(header *types.Header)
+
+func buildNextBlock(t *testing.T, _bor consensus.Engine, chain *core.BlockChain, parentBlock *types.Block, signer []byte, borConfig *params.BorConfig, txs []*types.Transaction, currentValidators []*valset.Validator, opts ...Option) *types.Block {
 	t.Helper()
 
-	header := block.Header()
-	header.Number.Add(header.Number, big.NewInt(1))
+	header := &types.Header{
+		Number:     big.NewInt(int64(parentBlock.Number().Uint64() + 1)),
+		Difficulty: big.NewInt(int64(parentBlock.Difficulty().Uint64())),
+		GasLimit:   parentBlock.GasLimit(),
+		ParentHash: parentBlock.Hash(),
+	}
 	number := header.Number.Uint64()
 
 	if signer == nil {
 		signer = getSignerKey(header.Number.Uint64())
 	}
 
-	header.ParentHash = block.Hash()
-	header.Time += bor.CalcProducerDelay(header.Number.Uint64(), 0, borConfig)
+	header.Time = parentBlock.Time() + bor.CalcProducerDelay(header.Number.Uint64(), 0, borConfig)
 	header.Extra = make([]byte, 32+65) // vanity + extraSeal
 
-	currentValidators := []*valset.Validator{valset.NewValidator(addr, 10)}
+	isSpanStart := IsSpanStart(number)
+	isSprintEnd := IsSprintEnd(number)
 
-	isSpanEnd := (number+1)%spanSize == 0
-	isSpanStart := number%spanSize == 0
-	isSprintEnd := (header.Number.Uint64()+1)%sprintSize == 0
-
-	if isSpanEnd {
-		_, heimdallSpan := loadSpanFromFile(t)
-		// this is to stash the validator bytes in the header
-		currentValidators = heimdallSpan.ValidatorSet.Validators
-	} else if isSpanStart {
-		header.Difficulty = new(big.Int).SetInt64(3)
+	if isSpanStart {
+		header.Difficulty = new(big.Int).SetInt64(int64(len(currentValidators)))
 	}
 
 	if isSprintEnd {
@@ -132,27 +150,87 @@ func buildNextBlock(t *testing.T, _bor *bor.Bor, chain *core.BlockChain, block *
 	}
 
 	if chain.Config().IsLondon(header.Number) {
-		header.BaseFee = misc.CalcBaseFee(chain.Config(), block.Header())
+		header.BaseFee = misc.CalcBaseFee(chain.Config(), parentBlock.Header())
 
-		if !chain.Config().IsLondon(block.Number()) {
-			parentGasLimit := block.GasLimit() * params.ElasticityMultiplier
+		if !chain.Config().IsLondon(parentBlock.Number()) {
+			parentGasLimit := parentBlock.GasLimit() * params.ElasticityMultiplier
 			header.GasLimit = core.CalcGasLimit(parentGasLimit, parentGasLimit)
 		}
 	}
 
+	for _, opt := range opts {
+		opt(header)
+	}
+
 	state, err := chain.State()
 	if err != nil {
 		t.Fatalf("%s", err)
 	}
 
-	_, err = _bor.FinalizeAndAssemble(chain, header, state, nil, nil, nil)
-	if err != nil {
-		t.Fatalf("%s", err)
+	b := &blockGen{header: header}
+	for _, tx := range txs {
+		b.addTxWithChain(chain, state, tx, addr)
 	}
 
-	sign(t, header, signer, borConfig)
+	// Finalize and seal the block
+	block, _ := _bor.FinalizeAndAssemble(chain, b.header, state, b.txs, nil, b.receipts)
 
-	return types.NewBlockWithHeader(header)
+	// Write state changes to db
+	root, err := state.Commit(chain.Config().IsEIP158(b.header.Number))
+	if err != nil {
+		panic(fmt.Sprintf("state write error: %v", err))
+	}
+
+	if err := state.Database().TrieDB().Commit(root, false, nil); err != nil {
+		panic(fmt.Sprintf("trie write error: %v", err))
+	}
+
+	res := make(chan *types.Block, 1)
+
+	err = _bor.Seal(chain, block, res, nil)
+	if err != nil {
+		// an error case - sign manually
+		sign(t, header, signer, borConfig)
+		return types.NewBlockWithHeader(header)
+	}
+
+	return <-res
+}
+
+type blockGen struct {
+	txs      []*types.Transaction
+	receipts []*types.Receipt
+	gasPool  *core.GasPool
+	header   *types.Header
+}
+
+func (b *blockGen) addTxWithChain(bc *core.BlockChain, statedb *state.StateDB, tx *types.Transaction, coinbase common.Address) {
+	if b.gasPool == nil {
+		b.setCoinbase(coinbase)
+	}
+
+	statedb.Prepare(tx.Hash(), len(b.txs))
+
+	receipt, err := core.ApplyTransaction(bc.Config(), bc, &b.header.Coinbase, b.gasPool, statedb, b.header, tx, &b.header.GasUsed, vm.Config{})
+	if err != nil {
+		panic(err)
+	}
+
+	b.txs = append(b.txs, tx)
+	b.receipts = append(b.receipts, receipt)
+}
+
+func (b *blockGen) setCoinbase(addr common.Address) {
+	if b.gasPool != nil {
+		if len(b.txs) > 0 {
+			panic("coinbase must be set before adding transactions")
+		}
+
+		panic("coinbase can only be set once")
+	}
+
+	b.header.Coinbase = addr
+	b.gasPool = new(core.GasPool).AddGas(b.header.GasLimit)
 }
 
 func sign(t *testing.T, header *types.Header, signer []byte, c *params.BorConfig) {
@@ -204,13 +282,80 @@ func loadSpanFromFile(t *testing.T) (*heimdall.SpanResponse, *span.HeimdallSpan)
 func getSignerKey(number uint64) []byte {
 	signerKey := privKey
 
-	isSpanStart := number%spanSize == 0
-	if isSpanStart {
+	if IsSpanStart(number) {
 		// validator set in the new span has changed
 		signerKey = privKey2
 	}
 
-	_key, _ := hex.DecodeString(signerKey)
+	newKey, _ := hex.DecodeString(signerKey)
 
-	return _key
+	return newKey
+}
+
+func getMockedHeimdallClient(t *testing.T, heimdallSpan *span.HeimdallSpan) (*mocks.MockIHeimdallClient, *gomock.Controller) {
+	t.Helper()
+
+	ctrl := gomock.NewController(t)
+	h := mocks.NewMockIHeimdallClient(ctrl)
+
+	h.EXPECT().Span(gomock.Any(), uint64(1)).Return(heimdallSpan, nil).AnyTimes()
+
+	h.EXPECT().StateSyncEvents(gomock.Any(), gomock.Any(), gomock.Any()).
+		Return([]*clerk.EventRecordWithTime{getSampleEventRecord(t)}, nil).AnyTimes()
+
+	return h, ctrl
+}
+
+func generateFakeStateSyncEvents(sample *clerk.EventRecordWithTime, count int) []*clerk.EventRecordWithTime {
+	events := make([]*clerk.EventRecordWithTime, count)
+	event := *sample
+	event.ID = 1
+	events[0] = &clerk.EventRecordWithTime{}
+	*events[0] = event
+
+	for i := 1; i < count; i++ {
+		event.ID = uint64(i)
+		event.Time = event.Time.Add(1 * time.Second)
+		events[i] = &clerk.EventRecordWithTime{}
+		*events[i] = event
+	}
+
+	return events
+}
+
+func buildStateEvent(sample *clerk.EventRecordWithTime, id uint64, timeStamp int64) *clerk.EventRecordWithTime {
+	event := *sample
+	event.ID = id
+	event.Time = time.Unix(timeStamp, 0)
+
+	return &event
+}
+
+func getSampleEventRecord(t *testing.T) *clerk.EventRecordWithTime {
+	t.Helper()
+
+	eventRecords := stateSyncEventsPayload(t)
+	eventRecords.Result[0].Time = time.Unix(1, 0)
+
+	return eventRecords.Result[0]
+}
+
+func newGwei(n int64) *big.Int {
+	return new(big.Int).Mul(big.NewInt(n), big.NewInt(params.GWei))
+}
+
+func IsSpanEnd(number uint64) bool {
+	return (number+1)%spanSize == 0
+}
+
+func IsSpanStart(number uint64) bool {
+	return number%spanSize == 0
+}
+
+func IsSprintStart(number uint64) bool {
+	return number%sprintSize == 0
+}
+
+func IsSprintEnd(number uint64) bool {
+	return (number+1)%sprintSize == 0
 }
diff --git a/tests/bor/mocks/IHeimdallClient.go b/tests/bor/mocks/IHeimdallClient.go
index 15e6a70990..15a09712f1 100644
--- a/tests/bor/mocks/IHeimdallClient.go
+++ b/tests/bor/mocks/IHeimdallClient.go
@@ -49,19 +49,34 @@ func (mr *MockIHeimdallClientMockRecorder) Close() *gomock.Call {
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Close", reflect.TypeOf((*MockIHeimdallClient)(nil).Close))
 }
 
-// FetchLatestCheckpoint mocks base method.
-func (m *MockIHeimdallClient) FetchLatestCheckpoint(arg0 context.Context) (*checkpoint.Checkpoint, error) {
+// FetchCheckpoint mocks base method.
+func (m *MockIHeimdallClient) FetchCheckpoint(arg0 context.Context, arg1 int64) (*checkpoint.Checkpoint, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "FetchLatestCheckpoint", arg0)
+	ret := m.ctrl.Call(m, "FetchCheckpoint", arg0, arg1)
 	ret0, _ := ret[0].(*checkpoint.Checkpoint)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
-// FetchLatestCheckpoint indicates an expected call of FetchLatestCheckpoint.
-func (mr *MockIHeimdallClientMockRecorder) FetchLatestCheckpoint(arg0 interface{}) *gomock.Call {
+// FetchCheckpoint indicates an expected call of FetchCheckpoint.
+func (mr *MockIHeimdallClientMockRecorder) FetchCheckpoint(arg0, arg1 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FetchLatestCheckpoint", reflect.TypeOf((*MockIHeimdallClient)(nil).FetchLatestCheckpoint), arg0)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FetchCheckpoint", reflect.TypeOf((*MockIHeimdallClient)(nil).FetchCheckpoint), arg0, arg1)
+}
+
+// FetchCheckpointCount mocks base method.
+func (m *MockIHeimdallClient) FetchCheckpointCount(arg0 context.Context) (int64, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "FetchCheckpointCount", arg0)
+	ret0, _ := ret[0].(int64)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// FetchCheckpointCount indicates an expected call of FetchCheckpointCount.
+func (mr *MockIHeimdallClientMockRecorder) FetchCheckpointCount(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "FetchCheckpointCount", reflect.TypeOf((*MockIHeimdallClient)(nil).FetchCheckpointCount), arg0)
 }
 
 // Span mocks base method.
diff --git a/tests/bor/testdata/genesis.json b/tests/bor/testdata/genesis.json
index b5767b3ed3..f096ad1cec 100644
--- a/tests/bor/testdata/genesis.json
+++ b/tests/bor/testdata/genesis.json
@@ -52,6 +52,9 @@
     },
     "71562b71999873DB5b286dF957af199Ec94617F7": {
       "balance": "0x3635c9adc5dea00000"
+    },
+    "9fB29AAc15b9A4B7F17c3385939b007540f4d791": {
+      "balance": "0x3635c9adc5dea00000"
     }
   },
   "number": "0x0",
diff --git a/tests/fuzzers/les/les-fuzzer.go b/tests/fuzzers/les/les-fuzzer.go
index 3e10171873..c379d1f08d 100644
--- a/tests/fuzzers/les/les-fuzzer.go
+++ b/tests/fuzzers/les/les-fuzzer.go
@@ -80,7 +80,7 @@ func makechain() (bc *core.BlockChain, addrHashes, txHashes []common.Hash) {
 			addrHashes = append(addrHashes, crypto.Keccak256Hash(addr[:]))
 			txHashes = append(txHashes, tx.Hash())
 		})
-	bc, _ = core.NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	bc, _ = core.NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if _, err := bc.InsertChain(blocks); err != nil {
 		panic(err)
 	}
diff --git a/tests/fuzzers/snap/fuzz_handler.go b/tests/fuzzers/snap/fuzz_handler.go
index 1ae61df29d..d58221b500 100644
--- a/tests/fuzzers/snap/fuzz_handler.go
+++ b/tests/fuzzers/snap/fuzz_handler.go
@@ -79,7 +79,7 @@ func getChain() *core.BlockChain {
 		SnapshotWait:        true,
 	}
 	trieRoot = blocks[len(blocks)-1].Root()
-	bc, _ := core.NewBlockChain(db, cacheConf, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	bc, _ := core.NewBlockChain(db, cacheConf, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil, nil)
 	if _, err := bc.InsertChain(blocks); err != nil {
 		panic(err)
 	}