diff --git a/README.md b/README.md
index c6bc91af17..f308fb1011 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ https://camo.githubusercontent.com/915b7be44ada53c290eb157634330494ebe3e30a/6874
 )](https://godoc.org/github.com/ethereum/go-ethereum)
 [![Go Report Card](https://goreportcard.com/badge/github.com/ethereum/go-ethereum)](https://goreportcard.com/report/github.com/ethereum/go-ethereum)
 [![Travis](https://travis-ci.org/ethereum/go-ethereum.svg?branch=master)](https://travis-ci.org/ethereum/go-ethereum)
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/ethereum/go-ethereum?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+[![Discord](https://img.shields.io/badge/discord-join%20chat-blue.svg)](https://discord.gg/nthXNEv)
 
 Automated builds are available for stable releases and the unstable master branch.
 Binary archives are published at https://geth.ethereum.org/downloads/.
diff --git a/cmd/clef/main.go b/cmd/clef/main.go
index 85704754de..f363a86f2c 100644
--- a/cmd/clef/main.go
+++ b/cmd/clef/main.go
@@ -225,7 +225,7 @@ func initializeSecrets(c *cli.Context) error {
 	if _, err := os.Stat(location); err == nil {
 		return fmt.Errorf("file %v already exists, will not overwrite", location)
 	}
-	err = ioutil.WriteFile(location, masterSeed, 0700)
+	err = ioutil.WriteFile(location, masterSeed, 0400)
 	if err != nil {
 		return err
 	}
@@ -540,14 +540,14 @@ func readMasterKey(ctx *cli.Context) ([]byte, error) {
 
 // checkFile is a convenience function to check if a file
 // * exists
-// * is mode 0600
+// * is mode 0400
 func checkFile(filename string) error {
 	info, err := os.Stat(filename)
 	if err != nil {
 		return fmt.Errorf("failed stat on %s: %v", filename, err)
 	}
 	// Check the unix permission bits
-	if info.Mode().Perm()&077 != 0 {
+	if info.Mode().Perm()&0377 != 0 {
 		return fmt.Errorf("file (%v) has insecure file permissions (%v)", filename, info.Mode().String())
 	}
 	return nil
diff --git a/cmd/evm/disasm.go b/cmd/evm/disasm.go
index 4a442cf784..69f611e39b 100644
--- a/cmd/evm/disasm.go
+++ b/cmd/evm/disasm.go
@@ -44,7 +44,7 @@ func disasmCmd(ctx *cli.Context) error {
 		return err
 	}
 
-	code := strings.TrimSpace(string(in[:]))
+	code := strings.TrimSpace(string(in))
 	fmt.Printf("%v\n", code)
 	return asm.PrintDisassembled(code)
 }
diff --git a/common/bytes.go b/common/bytes.go
index cbab2c3fa9..0c257a1ee0 100644
--- a/common/bytes.go
+++ b/common/bytes.go
@@ -100,7 +100,7 @@ func Hex2BytesFixed(str string, flen int) []byte {
 		return h[len(h)-flen:]
 	}
 	hh := make([]byte, flen)
-	copy(hh[flen-len(h):flen], h[:])
+	copy(hh[flen-len(h):flen], h)
 	return hh
 }
 
diff --git a/consensus/clique/clique.go b/consensus/clique/clique.go
index 0ff72e55c6..2b69141c12 100644
--- a/consensus/clique/clique.go
+++ b/consensus/clique/clique.go
@@ -93,27 +93,33 @@ var (
 
 	// errMissingSignature is returned if a block's extra-data section doesn't seem
 	// to contain a 65 byte secp256k1 signature.
-	errMissingSignature = errors.New("extra-data 65 byte suffix signature missing")
+	errMissingSignature = errors.New("extra-data 65 byte signature suffix missing")
 
 	// errExtraSigners is returned if non-checkpoint block contain signer data in
 	// their extra-data fields.
 	errExtraSigners = errors.New("non-checkpoint block contains extra signer list")
 
 	// errInvalidCheckpointSigners is returned if a checkpoint block contains an
-	// invalid list of signers (i.e. non divisible by 20 bytes, or not the correct
-	// ones).
+	// invalid list of signers (i.e. non divisible by 20 bytes).
 	errInvalidCheckpointSigners = errors.New("invalid signer list on checkpoint block")
 
+	// errMismatchingCheckpointSigners is returned if a checkpoint block contains a
+	// list of signers different than the one the local node calculated.
+	errMismatchingCheckpointSigners = errors.New("mismatching signer list on checkpoint block")
+
 	// errInvalidMixDigest is returned if a block's mix digest is non-zero.
 	errInvalidMixDigest = errors.New("non-zero mix digest")
 
 	// errInvalidUncleHash is returned if a block contains an non-empty uncle list.
 	errInvalidUncleHash = errors.New("non empty uncle hash")
 
-	// errInvalidDifficulty is returned if the difficulty of a block is not either
-	// of 1 or 2, or if the value does not match the turn of the signer.
+	// errInvalidDifficulty is returned if the difficulty of a block neither 1 or 2.
 	errInvalidDifficulty = errors.New("invalid difficulty")
 
+	// errWrongDifficulty is returned if the difficulty of a block doesn't match the
+	// turn of the signer.
+	errWrongDifficulty = errors.New("wrong difficulty")
+
 	// ErrInvalidTimestamp is returned if the timestamp of a block is lower than
 	// the previous block's timestamp + the minimum block period.
 	ErrInvalidTimestamp = errors.New("invalid timestamp")
@@ -122,8 +128,12 @@ var (
 	// be modified via out-of-range or non-contiguous headers.
 	errInvalidVotingChain = errors.New("invalid voting chain")
 
-	// errUnauthorized is returned if a header is signed by a non-authorized entity.
-	errUnauthorized = errors.New("unauthorized")
+	// errUnauthorizedSigner is returned if a header is signed by a non-authorized entity.
+	errUnauthorizedSigner = errors.New("unauthorized signer")
+
+	// errRecentlySigned is returned if a header is signed by an authorized entity
+	// that already signed a header recently, thus is temporarily not allowed to.
+	errRecentlySigned = errors.New("recently signed")
 
 	// errWaitTransactions is returned if an empty block is attempted to be sealed
 	// on an instant chain (0 second period). It's important to refuse these as the
@@ -205,6 +215,9 @@ type Clique struct {
 	signer common.Address // Ethereum address of the signing key
 	signFn SignerFn       // Signer function to authorize hashes with
 	lock   sync.RWMutex   // Protects the signer fields
+
+	// The fields below are for testing only
+	fakeDiff bool // Skip difficulty verifications
 }
 
 // New creates a Clique proof-of-authority consensus engine with the initial
@@ -359,7 +372,7 @@ func (c *Clique) verifyCascadingFields(chain consensus.ChainReader, header *type
 		}
 		extraSuffix := len(header.Extra) - extraSeal
 		if !bytes.Equal(header.Extra[extraVanity:extraSuffix], signers) {
-			return errInvalidCheckpointSigners
+			return errMismatchingCheckpointSigners
 		}
 	}
 	// All basic checks passed, verify the seal and return
@@ -481,23 +494,25 @@ func (c *Clique) verifySeal(chain consensus.ChainReader, header *types.Header, p
 		return err
 	}
 	if _, ok := snap.Signers[signer]; !ok {
-		return errUnauthorized
+		return errUnauthorizedSigner
 	}
 	for seen, recent := range snap.Recents {
 		if recent == signer {
 			// Signer is among recents, only fail if the current block doesn't shift it out
 			if limit := uint64(len(snap.Signers)/2 + 1); seen > number-limit {
-				return errUnauthorized
+				return errRecentlySigned
 			}
 		}
 	}
 	// Ensure that the difficulty corresponds to the turn-ness of the signer
-	inturn := snap.inturn(header.Number.Uint64(), signer)
-	if inturn && header.Difficulty.Cmp(diffInTurn) != 0 {
-		return errInvalidDifficulty
-	}
-	if !inturn && header.Difficulty.Cmp(diffNoTurn) != 0 {
-		return errInvalidDifficulty
+	if !c.fakeDiff {
+		inturn := snap.inturn(header.Number.Uint64(), signer)
+		if inturn && header.Difficulty.Cmp(diffInTurn) != 0 {
+			return errWrongDifficulty
+		}
+		if !inturn && header.Difficulty.Cmp(diffNoTurn) != 0 {
+			return errWrongDifficulty
+		}
 	}
 	return nil
 }
@@ -613,7 +628,7 @@ func (c *Clique) Seal(chain consensus.ChainReader, block *types.Block, results c
 		return err
 	}
 	if _, authorized := snap.Signers[signer]; !authorized {
-		return errUnauthorized
+		return errUnauthorizedSigner
 	}
 	// If we're amongst the recent signers, wait for the next block
 	for seen, recent := range snap.Recents {
diff --git a/consensus/clique/snapshot.go b/consensus/clique/snapshot.go
index 2333d69247..54d4555f3b 100644
--- a/consensus/clique/snapshot.go
+++ b/consensus/clique/snapshot.go
@@ -57,12 +57,12 @@ type Snapshot struct {
 	Tally   map[common.Address]Tally    `json:"tally"`   // Current vote tally to avoid recalculating
 }
 
-// signers implements the sort interface to allow sorting a list of addresses
-type signers []common.Address
+// signersAscending implements the sort interface to allow sorting a list of addresses
+type signersAscending []common.Address
 
-func (s signers) Len() int           { return len(s) }
-func (s signers) Less(i, j int) bool { return bytes.Compare(s[i][:], s[j][:]) < 0 }
-func (s signers) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s signersAscending) Len() int           { return len(s) }
+func (s signersAscending) Less(i, j int) bool { return bytes.Compare(s[i][:], s[j][:]) < 0 }
+func (s signersAscending) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 
 // newSnapshot creates a new snapshot with the specified startup parameters. This
 // method does not initialize the set of recent signers, so only ever use if for
@@ -214,11 +214,11 @@ func (s *Snapshot) apply(headers []*types.Header) (*Snapshot, error) {
 			return nil, err
 		}
 		if _, ok := snap.Signers[signer]; !ok {
-			return nil, errUnauthorized
+			return nil, errUnauthorizedSigner
 		}
 		for _, recent := range snap.Recents {
 			if recent == signer {
-				return nil, errUnauthorized
+				return nil, errRecentlySigned
 			}
 		}
 		snap.Recents[number] = signer
@@ -298,7 +298,7 @@ func (s *Snapshot) signers() []common.Address {
 	for sig := range s.Signers {
 		sigs = append(sigs, sig)
 	}
-	sort.Sort(signers(sigs))
+	sort.Sort(signersAscending(sigs))
 	return sigs
 }
 
diff --git a/consensus/clique/snapshot_test.go b/consensus/clique/snapshot_test.go
index 17719884f0..71fe7ce8b2 100644
--- a/consensus/clique/snapshot_test.go
+++ b/consensus/clique/snapshot_test.go
@@ -19,24 +19,18 @@ package clique
 import (
 	"bytes"
 	"crypto/ecdsa"
-	"math/big"
+	"sort"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/rawdb"
 	"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/ethdb"
 	"github.com/ethereum/go-ethereum/params"
 )
 
-type testerVote struct {
-	signer string
-	voted  string
-	auth   bool
-}
-
 // testerAccountPool is a pool to maintain currently active tester accounts,
 // mapped from textual names used in the tests below to actual Ethereum private
 // keys capable of signing transactions.
@@ -50,17 +44,26 @@ func newTesterAccountPool() *testerAccountPool {
 	}
 }
 
-func (ap *testerAccountPool) sign(header *types.Header, signer string) {
-	// Ensure we have a persistent key for the signer
-	if ap.accounts[signer] == nil {
-		ap.accounts[signer], _ = crypto.GenerateKey()
+// checkpoint creates a Clique checkpoint signer section from the provided list
+// of authorized signers and embeds it into the provided header.
+func (ap *testerAccountPool) checkpoint(header *types.Header, signers []string) {
+	auths := make([]common.Address, len(signers))
+	for i, signer := range signers {
+		auths[i] = ap.address(signer)
+	}
+	sort.Sort(signersAscending(auths))
+	for i, auth := range auths {
+		copy(header.Extra[extraVanity+i*common.AddressLength:], auth.Bytes())
 	}
-	// Sign the header and embed the signature in extra data
-	sig, _ := crypto.Sign(sigHash(header).Bytes(), ap.accounts[signer])
-	copy(header.Extra[len(header.Extra)-65:], sig)
 }
 
+// address retrieves the Ethereum address of a tester account by label, creating
+// a new account if no previous one exists yet.
 func (ap *testerAccountPool) address(account string) common.Address {
+	// Return the zero account for non-addresses
+	if account == "" {
+		return common.Address{}
+	}
 	// Ensure we have a persistent key for the account
 	if ap.accounts[account] == nil {
 		ap.accounts[account], _ = crypto.GenerateKey()
@@ -69,32 +72,38 @@ func (ap *testerAccountPool) address(account string) common.Address {
 	return crypto.PubkeyToAddress(ap.accounts[account].PublicKey)
 }
 
-// testerChainReader implements consensus.ChainReader to access the genesis
-// block. All other methods and requests will panic.
-type testerChainReader struct {
-	db ethdb.Database
-}
-
-func (r *testerChainReader) Config() *params.ChainConfig                 { return params.AllCliqueProtocolChanges }
-func (r *testerChainReader) CurrentHeader() *types.Header                { panic("not supported") }
-func (r *testerChainReader) GetHeader(common.Hash, uint64) *types.Header { panic("not supported") }
-func (r *testerChainReader) GetBlock(common.Hash, uint64) *types.Block   { panic("not supported") }
-func (r *testerChainReader) GetHeaderByHash(common.Hash) *types.Header   { panic("not supported") }
-func (r *testerChainReader) GetHeaderByNumber(number uint64) *types.Header {
-	if number == 0 {
-		return rawdb.ReadHeader(r.db, rawdb.ReadCanonicalHash(r.db, 0), 0)
+// sign calculates a Clique digital signature for the given block and embeds it
+// back into the header.
+func (ap *testerAccountPool) sign(header *types.Header, signer string) {
+	// Ensure we have a persistent key for the signer
+	if ap.accounts[signer] == nil {
+		ap.accounts[signer], _ = crypto.GenerateKey()
 	}
-	return nil
+	// Sign the header and embed the signature in extra data
+	sig, _ := crypto.Sign(sigHash(header).Bytes(), ap.accounts[signer])
+	copy(header.Extra[len(header.Extra)-extraSeal:], sig)
 }
 
-// Tests that voting is evaluated correctly for various simple and complex scenarios.
-func TestVoting(t *testing.T) {
+// testerVote represents a single block signed by a parcitular account, where
+// the account may or may not have cast a Clique vote.
+type testerVote struct {
+	signer     string
+	voted      string
+	auth       bool
+	checkpoint []string
+	newbatch   bool
+}
+
+// Tests that Clique signer voting is evaluated correctly for various simple and
+// complex scenarios, as well as that a few special corner cases fail correctly.
+func TestClique(t *testing.T) {
 	// Define the various voting scenarios to test
 	tests := []struct {
 		epoch   uint64
 		signers []string
 		votes   []testerVote
 		results []string
+		failure error
 	}{
 		{
 			// Single signer, no votes cast
@@ -322,10 +331,49 @@ func TestVoting(t *testing.T) {
 			votes: []testerVote{
 				{signer: "A", voted: "C", auth: true},
 				{signer: "B"},
-				{signer: "A"}, // Checkpoint block, (don't vote here, it's validated outside of snapshots)
+				{signer: "A", checkpoint: []string{"A", "B"}},
 				{signer: "B", voted: "C", auth: true},
 			},
 			results: []string{"A", "B"},
+		}, {
+			// An unauthorized signer should not be able to sign blocks
+			signers: []string{"A"},
+			votes: []testerVote{
+				{signer: "B"},
+			},
+			failure: errUnauthorizedSigner,
+		}, {
+			// An authorized signer that signed recenty should not be able to sign again
+			signers: []string{"A", "B"},
+			votes: []testerVote{
+				{signer: "A"},
+				{signer: "A"},
+			},
+			failure: errRecentlySigned,
+		}, {
+			// Recent signatures should not reset on checkpoint blocks imported in a batch
+			epoch:   3,
+			signers: []string{"A", "B", "C"},
+			votes: []testerVote{
+				{signer: "A"},
+				{signer: "B"},
+				{signer: "A", checkpoint: []string{"A", "B", "C"}},
+				{signer: "A"},
+			},
+			failure: errRecentlySigned,
+		}, {
+			// Recent signatures should not reset on checkpoint blocks imported in a new
+			// batch (https://github.com/ethereum/go-ethereum/issues/17593). Whilst this
+			// seems overly specific and weird, it was a Rinkeby consensus split.
+			epoch:   3,
+			signers: []string{"A", "B", "C"},
+			votes: []testerVote{
+				{signer: "A"},
+				{signer: "B"},
+				{signer: "A", checkpoint: []string{"A", "B", "C"}},
+				{signer: "A", newbatch: true},
+			},
+			failure: errRecentlySigned,
 		},
 	}
 	// Run through the scenarios and test them
@@ -356,28 +404,78 @@ func TestVoting(t *testing.T) {
 		genesis.Commit(db)
 
 		// Assemble a chain of headers from the cast votes
-		headers := make([]*types.Header, len(tt.votes))
-		for j, vote := range tt.votes {
-			headers[j] = &types.Header{
-				Number:   big.NewInt(int64(j) + 1),
-				Time:     big.NewInt(int64(j) * 15),
-				Coinbase: accounts.address(vote.voted),
-				Extra:    make([]byte, extraVanity+extraSeal),
+		config := *params.TestChainConfig
+		config.Clique = &params.CliqueConfig{
+			Period: 1,
+			Epoch:  tt.epoch,
+		}
+		engine := New(config.Clique, db)
+		engine.fakeDiff = true
+
+		blocks, _ := core.GenerateChain(&config, genesis.ToBlock(db), engine, db, len(tt.votes), func(j int, gen *core.BlockGen) {
+			// Cast the vote contained in this block
+			gen.SetCoinbase(accounts.address(tt.votes[j].voted))
+			if tt.votes[j].auth {
+				var nonce types.BlockNonce
+				copy(nonce[:], nonceAuthVote)
+				gen.SetNonce(nonce)
 			}
+		})
+		// Iterate through the blocks and seal them individually
+		for j, block := range blocks {
+			// Geth the header and prepare it for signing
+			header := block.Header()
 			if j > 0 {
-				headers[j].ParentHash = headers[j-1].Hash()
+				header.ParentHash = blocks[j-1].Hash()
 			}
-			if vote.auth {
-				copy(headers[j].Nonce[:], nonceAuthVote)
+			header.Extra = make([]byte, extraVanity+extraSeal)
+			if auths := tt.votes[j].checkpoint; auths != nil {
+				header.Extra = make([]byte, extraVanity+len(auths)*common.AddressLength+extraSeal)
+				accounts.checkpoint(header, auths)
 			}
-			accounts.sign(headers[j], vote.signer)
+			header.Difficulty = diffInTurn // Ignored, we just need a valid number
+
+			// Generate the signature, embed it into the header and the block
+			accounts.sign(header, tt.votes[j].signer)
+			blocks[j] = block.WithSeal(header)
+		}
+		// Split the blocks up into individual import batches (cornercase testing)
+		batches := [][]*types.Block{nil}
+		for j, block := range blocks {
+			if tt.votes[j].newbatch {
+				batches = append(batches, nil)
+			}
+			batches[len(batches)-1] = append(batches[len(batches)-1], block)
 		}
 		// Pass all the headers through clique and ensure tallying succeeds
-		head := headers[len(headers)-1]
-
-		snap, err := New(&params.CliqueConfig{Epoch: tt.epoch}, db).snapshot(&testerChainReader{db: db}, head.Number.Uint64(), head.Hash(), headers)
+		chain, err := core.NewBlockChain(db, nil, &config, engine, vm.Config{})
 		if err != nil {
-			t.Errorf("test %d: failed to create voting snapshot: %v", i, err)
+			t.Errorf("test %d: failed to create test chain: %v", i, err)
+			continue
+		}
+		failed := false
+		for j := 0; j < len(batches)-1; j++ {
+			if k, err := chain.InsertChain(batches[j]); err != nil {
+				t.Errorf("test %d: failed to import batch %d, block %d: %v", i, j, k, err)
+				failed = true
+				break
+			}
+		}
+		if failed {
+			continue
+		}
+		if _, err = chain.InsertChain(batches[len(batches)-1]); err != tt.failure {
+			t.Errorf("test %d: failure mismatch: have %v, want %v", i, err, tt.failure)
+		}
+		if tt.failure != nil {
+			continue
+		}
+		// No failure was produced or requested, generate the final voting snapshot
+		head := blocks[len(blocks)-1]
+
+		snap, err := engine.snapshot(chain, head.NumberU64(), head.Hash(), nil)
+		if err != nil {
+			t.Errorf("test %d: failed to retrieve voting snapshot: %v", i, err)
 			continue
 		}
 		// Verify the final list of signers against the expected ones
diff --git a/core/chain_indexer.go b/core/chain_indexer.go
index 89ee75eb29..4bdd4ba1c8 100644
--- a/core/chain_indexer.go
+++ b/core/chain_indexer.go
@@ -445,7 +445,7 @@ func (c *ChainIndexer) AddChildIndexer(indexer *ChainIndexer) {
 func (c *ChainIndexer) loadValidSections() {
 	data, _ := c.indexDb.Get([]byte("count"))
 	if len(data) == 8 {
-		c.storedSections = binary.BigEndian.Uint64(data[:])
+		c.storedSections = binary.BigEndian.Uint64(data)
 	}
 }
 
diff --git a/core/chain_makers.go b/core/chain_makers.go
index de0fc6be9e..3516734772 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -67,6 +67,11 @@ func (b *BlockGen) SetExtra(data []byte) {
 	b.header.Extra = data
 }
 
+// SetNonce sets the nonce field of the generated block.
+func (b *BlockGen) SetNonce(nonce types.BlockNonce) {
+	b.header.Nonce = nonce
+}
+
 // AddTx adds a transaction to the generated block. If no coinbase has
 // been set, the block's coinbase is set to the zero address.
 //
@@ -190,13 +195,14 @@ func GenerateChain(config *params.ChainConfig, parent *types.Block, engine conse
 		if config.DAOForkSupport && config.DAOForkBlock != nil && config.DAOForkBlock.Cmp(b.header.Number) == 0 {
 			misc.ApplyDAOHardFork(statedb)
 		}
-		// Execute any user modifications to the block and finalize it
+		// Execute any user modifications to the block
 		if gen != nil {
 			gen(i, b)
 		}
-
 		if b.engine != nil {
+			// Finalize and seal the block
 			block, _ := b.engine.Finalize(b.chainReader, b.header, statedb, b.txs, b.uncles, b.receipts)
+
 			// Write state changes to db
 			root, err := statedb.Commit(config.IsEIP158(b.header.Number))
 			if err != nil {
diff --git a/core/types/bloom9.go b/core/types/bloom9.go
index a76b6f33c5..d045c9e667 100644
--- a/core/types/bloom9.go
+++ b/core/types/bloom9.go
@@ -113,7 +113,7 @@ func LogsBloom(logs []*Log) *big.Int {
 }
 
 func bloom9(b []byte) *big.Int {
-	b = crypto.Keccak256(b[:])
+	b = crypto.Keccak256(b)
 
 	r := new(big.Int)
 
@@ -130,7 +130,7 @@ var Bloom9 = bloom9
 
 func BloomLookup(bin Bloom, topic bytesBacked) bool {
 	bloom := bin.Big()
-	cmp := bloom9(topic.Bytes()[:])
+	cmp := bloom9(topic.Bytes())
 
 	return bloom.And(bloom, cmp).Cmp(cmp) == 0
 }
diff --git a/eth/tracers/tracer.go b/eth/tracers/tracer.go
index feb57e0601..b519236f2d 100644
--- a/eth/tracers/tracer.go
+++ b/eth/tracers/tracer.go
@@ -124,7 +124,7 @@ func (mw *memoryWrapper) pushObject(vm *duktape.Context) {
 		ctx.Pop2()
 
 		ptr := ctx.PushFixedBuffer(len(blob))
-		copy(makeSlice(ptr, uint(len(blob))), blob[:])
+		copy(makeSlice(ptr, uint(len(blob))), blob)
 		return 1
 	})
 	vm.PutPropString(obj, "slice")
@@ -204,7 +204,7 @@ func (dw *dbWrapper) pushObject(vm *duktape.Context) {
 		code := dw.db.GetCode(common.BytesToAddress(popSlice(ctx)))
 
 		ptr := ctx.PushFixedBuffer(len(code))
-		copy(makeSlice(ptr, uint(len(code))), code[:])
+		copy(makeSlice(ptr, uint(len(code))), code)
 		return 1
 	})
 	vm.PutPropString(obj, "getCode")
@@ -268,7 +268,7 @@ func (cw *contractWrapper) pushObject(vm *duktape.Context) {
 		blob := cw.contract.Input
 
 		ptr := ctx.PushFixedBuffer(len(blob))
-		copy(makeSlice(ptr, uint(len(blob))), blob[:])
+		copy(makeSlice(ptr, uint(len(blob))), blob)
 		return 1
 	})
 	vm.PutPropString(obj, "getInput")
@@ -584,7 +584,7 @@ func (jst *Tracer) GetResult() (json.RawMessage, error) {
 
 		case []byte:
 			ptr := jst.vm.PushFixedBuffer(len(val))
-			copy(makeSlice(ptr, uint(len(val))), val[:])
+			copy(makeSlice(ptr, uint(len(val))), val)
 
 		case common.Address:
 			ptr := jst.vm.PushFixedBuffer(20)
diff --git a/les/distributor.go b/les/distributor.go
index d3f6b21d18..f90765b624 100644
--- a/les/distributor.go
+++ b/les/distributor.go
@@ -114,7 +114,9 @@ func (d *requestDistributor) loop() {
 			d.lock.Lock()
 			elem := d.reqQueue.Front()
 			for elem != nil {
-				close(elem.Value.(*distReq).sentChn)
+				req := elem.Value.(*distReq)
+				close(req.sentChn)
+				req.sentChn = nil
 				elem = elem.Next()
 			}
 			d.lock.Unlock()
diff --git a/miner/worker_test.go b/miner/worker_test.go
index 6de1177cdc..ad10d48efa 100644
--- a/miner/worker_test.go
+++ b/miner/worker_test.go
@@ -161,6 +161,7 @@ func testPendingStateAndBlock(t *testing.T, chainConfig *params.ChainConfig, eng
 		t.Errorf("account balance mismatch: have %d, want %d", balance, 1000)
 	}
 	b.txPool.AddLocals(newTxs)
+
 	// Ensure the new tx events has been processed
 	time.Sleep(100 * time.Millisecond)
 	block, state = w.pending()
diff --git a/p2p/discover/table.go b/p2p/discover/table.go
index 0a554bbeb4..a130b5494f 100644
--- a/p2p/discover/table.go
+++ b/p2p/discover/table.go
@@ -162,7 +162,7 @@ func (tab *Table) ReadRandomNodes(buf []*Node) (n int) {
 	var buckets [][]*Node
 	for _, b := range &tab.buckets {
 		if len(b.entries) > 0 {
-			buckets = append(buckets, b.entries[:])
+			buckets = append(buckets, b.entries)
 		}
 	}
 	if len(buckets) == 0 {
diff --git a/p2p/discv5/table.go b/p2p/discv5/table.go
index c793be5082..4f4b2426f4 100644
--- a/p2p/discv5/table.go
+++ b/p2p/discv5/table.go
@@ -123,7 +123,7 @@ func (tab *Table) readRandomNodes(buf []*Node) (n int) {
 	var buckets [][]*Node
 	for _, b := range &tab.buckets {
 		if len(b.entries) > 0 {
-			buckets = append(buckets, b.entries[:])
+			buckets = append(buckets, b.entries)
 		}
 	}
 	if len(buckets) == 0 {
diff --git a/swarm/api/http/server_test.go b/swarm/api/http/server_test.go
index 2acdbd1ad4..4a3ca0429a 100644
--- a/swarm/api/http/server_test.go
+++ b/swarm/api/http/server_test.go
@@ -501,7 +501,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 		var respbody []byte
 
 		url := srv.URL + "/bzz-raw:/"
-		if k[:] != "" {
+		if k != "" {
 			url += rootRef + "/" + k[1:] + "?content_type=text/plain"
 		}
 		resp, err = http.Get(url)
@@ -515,7 +515,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 			isexpectedfailrequest := false
 
 			for _, r := range expectedfailrequests {
-				if k[:] == r {
+				if k == r {
 					isexpectedfailrequest = true
 				}
 			}
@@ -530,7 +530,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 		var respbody []byte
 
 		url := srv.URL + "/bzz-hash:/"
-		if k[:] != "" {
+		if k != "" {
 			url += rootRef + "/" + k[1:]
 		}
 		resp, err = http.Get(url)
@@ -547,7 +547,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 			isexpectedfailrequest := false
 
 			for _, r := range expectedfailrequests {
-				if k[:] == r {
+				if k == r {
 					isexpectedfailrequest = true
 				}
 			}
@@ -599,7 +599,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 	} {
 		k := c.path
 		url := srv.URL + "/bzz-list:/"
-		if k[:] != "" {
+		if k != "" {
 			url += rootRef + "/" + k[1:]
 		}
 		t.Run("json list "+c.path, func(t *testing.T) {
@@ -618,7 +618,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 				isexpectedfailrequest := false
 
 				for _, r := range expectedfailrequests {
-					if k[:] == r {
+					if k == r {
 						isexpectedfailrequest = true
 					}
 				}
@@ -650,7 +650,7 @@ func testBzzGetPath(encrypted bool, t *testing.T) {
 					isexpectedfailrequest := false
 
 					for _, r := range expectedfailrequests {
-						if k[:] == r {
+						if k == r {
 							isexpectedfailrequest = true
 						}
 					}
diff --git a/swarm/pss/pss.go b/swarm/pss/pss.go
index b55c97fddf..b96649fea1 100644
--- a/swarm/pss/pss.go
+++ b/swarm/pss/pss.go
@@ -448,7 +448,7 @@ func (p *Pss) isSelfRecipient(msg *PssMsg) bool {
 // test match of leftmost bytes in given message to node's Kademlia address
 func (p *Pss) isSelfPossibleRecipient(msg *PssMsg) bool {
 	local := p.Kademlia.BaseAddr()
-	return bytes.Equal(msg.To[:], local[:len(msg.To)])
+	return bytes.Equal(msg.To, local[:len(msg.To)])
 }
 
 /////////////////////////////////////////////////////////////////////
diff --git a/swarm/storage/ldbstore.go b/swarm/storage/ldbstore.go
index 8ab7e60b36..bde627394e 100644
--- a/swarm/storage/ldbstore.go
+++ b/swarm/storage/ldbstore.go
@@ -85,7 +85,7 @@ func NewLDBStoreParams(storeparams *StoreParams, path string) *LDBStoreParams {
 	return &LDBStoreParams{
 		StoreParams: storeparams,
 		Path:        path,
-		Po:          func(k Address) (ret uint8) { return uint8(Proximity(storeparams.BaseKey[:], k[:])) },
+		Po:          func(k Address) (ret uint8) { return uint8(Proximity(storeparams.BaseKey, k[:])) },
 	}
 }
 
@@ -322,7 +322,7 @@ func (s *LDBStore) Export(out io.Writer) (int64, error) {
 		log.Trace("store.export", "dkey", fmt.Sprintf("%x", datakey), "dataidx", index.Idx, "po", po)
 		data, err := s.db.Get(datakey)
 		if err != nil {
-			log.Warn(fmt.Sprintf("Chunk %x found but could not be accessed: %v", key[:], err))
+			log.Warn(fmt.Sprintf("Chunk %x found but could not be accessed: %v", key, err))
 			continue
 		}
 
@@ -455,7 +455,7 @@ func (s *LDBStore) Cleanup() {
 			}
 
 			if !found {
-				log.Warn(fmt.Sprintf("Chunk %x found but count not be accessed with any po", key[:]))
+				log.Warn(fmt.Sprintf("Chunk %x found but count not be accessed with any po", key))
 				errorsFound++
 				continue
 			}
@@ -469,10 +469,10 @@ func (s *LDBStore) Cleanup() {
 		}
 
 		cs := int64(binary.LittleEndian.Uint64(c.sdata[:8]))
-		log.Trace("chunk", "key", fmt.Sprintf("%x", key[:]), "ck", fmt.Sprintf("%x", ck), "dkey", fmt.Sprintf("%x", datakey), "dataidx", index.Idx, "po", po, "len data", len(data), "len sdata", len(c.sdata), "size", cs)
+		log.Trace("chunk", "key", fmt.Sprintf("%x", key), "ck", fmt.Sprintf("%x", ck), "dkey", fmt.Sprintf("%x", datakey), "dataidx", index.Idx, "po", po, "len data", len(data), "len sdata", len(c.sdata), "size", cs)
 
 		if len(c.sdata) > ch.DefaultSize+8 {
-			log.Warn("chunk for cleanup", "key", fmt.Sprintf("%x", key[:]), "ck", fmt.Sprintf("%x", ck), "dkey", fmt.Sprintf("%x", datakey), "dataidx", index.Idx, "po", po, "len data", len(data), "len sdata", len(c.sdata), "size", cs)
+			log.Warn("chunk for cleanup", "key", fmt.Sprintf("%x", key), "ck", fmt.Sprintf("%x", ck), "dkey", fmt.Sprintf("%x", datakey), "dataidx", index.Idx, "po", po, "len data", len(data), "len sdata", len(c.sdata), "size", cs)
 			s.delete(index.Idx, getIndexKey(key[1:]), po)
 			removed++
 			errorsFound++
diff --git a/swarm/storage/ldbstore_test.go b/swarm/storage/ldbstore_test.go
index ae70ee2592..75b5d6aa95 100644
--- a/swarm/storage/ldbstore_test.go
+++ b/swarm/storage/ldbstore_test.go
@@ -74,7 +74,7 @@ func newTestDbStore(mock bool, trusted bool) (*testDbStore, func(), error) {
 
 func testPoFunc(k Address) (ret uint8) {
 	basekey := make([]byte, 32)
-	return uint8(Proximity(basekey[:], k[:]))
+	return uint8(Proximity(basekey, k[:]))
 }
 
 func (db *testDbStore) close() {
diff --git a/swarm/storage/types.go b/swarm/storage/types.go
index bc2af2cd78..8c70f45848 100644
--- a/swarm/storage/types.go
+++ b/swarm/storage/types.go
@@ -136,7 +136,7 @@ func (a Address) Log() string {
 }
 
 func (a Address) String() string {
-	return fmt.Sprintf("%064x", []byte(a)[:])
+	return fmt.Sprintf("%064x", []byte(a))
 }
 
 func (a Address) MarshalJSON() (out []byte, err error) {
diff --git a/whisper/whisperv5/filter_test.go b/whisper/whisperv5/filter_test.go
index c01c22668c..33138fb1a4 100644
--- a/whisper/whisperv5/filter_test.go
+++ b/whisper/whisperv5/filter_test.go
@@ -56,7 +56,7 @@ func generateFilter(t *testing.T, symmetric bool) (*Filter, error) {
 	f.Topics = make([][]byte, topicNum)
 	for i := 0; i < topicNum; i++ {
 		f.Topics[i] = make([]byte, 4)
-		mrand.Read(f.Topics[i][:])
+		mrand.Read(f.Topics[i])
 		f.Topics[i][0] = 0x01
 	}
 
diff --git a/whisper/whisperv6/filter_test.go b/whisper/whisperv6/filter_test.go
index 82e4aa0241..5ce99d9f6c 100644
--- a/whisper/whisperv6/filter_test.go
+++ b/whisper/whisperv6/filter_test.go
@@ -56,7 +56,7 @@ func generateFilter(t *testing.T, symmetric bool) (*Filter, error) {
 	f.Topics = make([][]byte, topicNum)
 	for i := 0; i < topicNum; i++ {
 		f.Topics[i] = make([]byte, 4)
-		mrand.Read(f.Topics[i][:])
+		mrand.Read(f.Topics[i])
 		f.Topics[i][0] = 0x01
 	}