diff --git a/eth/api_backend.go b/eth/api_backend.go
index 91f392f94f..c863997672 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"math/big"
 
+	ethereum "github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/math"
@@ -61,7 +62,7 @@ func (b *EthApiBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNum
 		block := b.eth.miner.PendingBlock()
 		return block.Header(), nil
 	}
-	// Otherwise resolve and return the block
+	// Otherwise resolve and return the header
 	if blockNr == rpc.LatestBlockNumber {
 		return b.eth.blockchain.CurrentBlock().Header(), nil
 	}
@@ -89,9 +90,12 @@ func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.
 	}
 	// Otherwise resolve the block number and return its state
 	header, err := b.HeaderByNumber(ctx, blockNr)
-	if header == nil || err != nil {
+	if err != nil {
 		return nil, nil, err
 	}
+	if header == nil {
+		return nil, nil, ethereum.NotFound
+	}
 	stateDb, err := b.eth.BlockChain().StateAt(header.Root)
 	return stateDb, header, err
 }
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index ab8478929f..babc2b996d 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -464,7 +464,7 @@ func (s *PublicBlockChainAPI) BlockNumber() *big.Int {
 // block numbers are also allowed.
 func (s *PublicBlockChainAPI) GetBalance(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*big.Int, error) {
 	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
-	if state == nil || err != nil {
+	if err != nil {
 		return nil, err
 	}
 	b := state.GetBalance(address)
@@ -551,7 +551,11 @@ func (s *PublicBlockChainAPI) GetUncleCountByBlockHash(ctx context.Context, bloc
 // GetCode returns the code stored at the given address in the state for the given block number.
 func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
 	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
-	if state == nil || err != nil {
+	if err != nil {
+		return nil, err
+	}
+	res, err := state.GetCode(ctx, address)
+	if len(res) == 0 || err != nil { // backwards compatibility
 		return nil, err
 	}
 	code := state.GetCode(address)
@@ -563,7 +567,11 @@ func (s *PublicBlockChainAPI) GetCode(ctx context.Context, address common.Addres
 // numbers are also allowed.
 func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.Address, key string, blockNr rpc.BlockNumber) (hexutil.Bytes, error) {
 	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
-	if state == nil || err != nil {
+	if err != nil {
+		return nil, err
+	}
+	res, err := state.GetState(ctx, address, common.HexToHash(key))
+	if err != nil {
 		return nil, err
 	}
 	res := state.GetState(address, common.HexToHash(key))
@@ -584,9 +592,10 @@ func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr
 	defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())
 
 	state, header, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
-	if state == nil || err != nil {
+	if err != nil {
 		return nil, common.Big0, err
 	}
+
 	// Set sender address or use a default if none specified
 	addr := args.From
 	if addr == (common.Address{}) {
@@ -940,7 +949,7 @@ func (s *PublicTransactionPoolAPI) GetRawTransactionByBlockHashAndIndex(ctx cont
 // GetTransactionCount returns the number of transactions the given address has sent for the given block number
 func (s *PublicTransactionPoolAPI) GetTransactionCount(ctx context.Context, address common.Address, blockNr rpc.BlockNumber) (*hexutil.Uint64, error) {
 	state, _, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
-	if state == nil || err != nil {
+	if err != nil {
 		return nil, err
 	}
 	nonce := state.GetNonce(address)
diff --git a/les/api_backend.go b/les/api_backend.go
index 0d2d31b673..0252138e35 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"math/big"
 
+	ethereum "github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/math"
@@ -59,7 +60,6 @@ func (b *LesApiBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNum
 	if blockNr == rpc.LatestBlockNumber || blockNr == rpc.PendingBlockNumber {
 		return b.eth.blockchain.CurrentHeader(), nil
 	}
-
 	return b.eth.blockchain.GetHeaderByNumberOdr(ctx, uint64(blockNr))
 }
 
@@ -73,9 +73,12 @@ func (b *LesApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 
 func (b *LesApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
 	header, err := b.HeaderByNumber(ctx, blockNr)
-	if header == nil || err != nil {
+	if err != nil {
 		return nil, nil, err
 	}
+	if header == nil {
+		return nil, nil, ethereum.NotFound
+	}
 	return light.NewState(ctx, header, b.eth.odr), header, nil
 }