diff --git a/cmd/geth/chaincmd.go b/cmd/geth/chaincmd.go
index 12bc1d7c66..4a9a7b11b5 100644
--- a/cmd/geth/chaincmd.go
+++ b/cmd/geth/chaincmd.go
@@ -31,7 +31,9 @@ import (
 	"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/eth/downloader"
 	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/trie"
 	"github.com/syndtr/goleveldb/leveldb/util"
@@ -71,7 +73,7 @@ It expects the genesis file as argument.`,
 The import command imports blocks from an RLP-encoded form. The form can be one file
 with several RLP-encoded blocks, or several files can be used.
 
-If only one file is used, import error will result in failure. If several files are used, 
+If only one file is used, import error will result in failure. If several files are used,
 processing will proceed even if an individual RLP-file import failure occurs.`,
 	}
 	exportCommand = cli.Command{
@@ -90,6 +92,23 @@ Requires a first argument of the file to write to.
 Optional second and third arguments control the first and
 last block to write. In this mode, the file will be appended
 if already existing.`,
+	}
+	copydbCommand = cli.Command{
+		Action:    utils.MigrateFlags(copyDb),
+		Name:      "copydb",
+		Usage:     "Create a local chain from a target chaindata folder",
+		ArgsUsage: "<sourceChaindataDir>",
+		Flags: []cli.Flag{
+			utils.DataDirFlag,
+			utils.CacheFlag,
+			utils.SyncModeFlag,
+			utils.FakePoWFlag,
+			utils.TestnetFlag,
+			utils.RinkebyFlag,
+		},
+		Category: "BLOCKCHAIN COMMANDS",
+		Description: `
+The first argument must be the directory containing the blockchain to download from`,
 	}
 	removedbCommand = cli.Command{
 		Action:    utils.MigrateFlags(removeDB),
@@ -268,6 +287,54 @@ func exportChain(ctx *cli.Context) error {
 	return nil
 }
 
+func copyDb(ctx *cli.Context) error {
+	// Ensure we have a source chain directory to copy
+	if len(ctx.Args()) != 1 {
+		utils.Fatalf("Source chaindata directory path argument missing")
+	}
+	// Initialize a new chain for the running node to sync into
+	stack := makeFullNode(ctx)
+	chain, chainDb := utils.MakeChain(ctx, stack)
+
+	syncmode := *utils.GlobalTextMarshaler(ctx, utils.SyncModeFlag.Name).(*downloader.SyncMode)
+	dl := downloader.New(syncmode, chainDb, new(event.TypeMux), chain, nil, nil)
+
+	// Create a source peer to satisfy downloader requests from
+	db, err := ethdb.NewLDBDatabase(ctx.Args().First(), ctx.GlobalInt(utils.CacheFlag.Name), 256)
+	if err != nil {
+		return err
+	}
+	hc, err := core.NewHeaderChain(db, chain.Config(), chain.Engine(), func() bool { return false })
+	if err != nil {
+		return err
+	}
+	peer := downloader.NewFakePeer("local", db, hc, dl)
+	if err = dl.RegisterPeer("local", 63, peer); err != nil {
+		return err
+	}
+	// Synchronise with the simulated peer
+	start := time.Now()
+
+	currentHeader := hc.CurrentHeader()
+	if err = dl.Synchronise("local", currentHeader.Hash(), hc.GetTd(currentHeader.Hash(), currentHeader.Number.Uint64()), syncmode); err != nil {
+		return err
+	}
+	for dl.Synchronising() {
+		time.Sleep(10 * time.Millisecond)
+	}
+	fmt.Printf("Database copy done in %v\n", time.Since(start))
+
+	// Compact the entire database to remove any sync overhead
+	start = time.Now()
+	fmt.Println("Compacting entire database...")
+	if err = chainDb.(*ethdb.LDBDatabase).LDB().CompactRange(util.Range{}); err != nil {
+		utils.Fatalf("Compaction failed: %v", err)
+	}
+	fmt.Printf("Compaction done in %v.\n\n", time.Since(start))
+
+	return nil
+}
+
 func removeDB(ctx *cli.Context) error {
 	stack, _ := makeConfigNode(ctx)
 
diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 8166c9ce80..88f3528f39 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -146,6 +146,7 @@ func init() {
 		initCommand,
 		importCommand,
 		exportCommand,
+		copydbCommand,
 		removedbCommand,
 		dumpCommand,
 		// See monitorcmd.go:
diff --git a/cmd/puppeth/wizard.go b/cmd/puppeth/wizard.go
index 3fdd639f80..5fbc11cb98 100644
--- a/cmd/puppeth/wizard.go
+++ b/cmd/puppeth/wizard.go
@@ -302,8 +302,10 @@ func (w *wizard) readJSON() string {
 }
 
 // readIPAddress reads a single line from stdin, trimming if from spaces and
-// converts it to a network IP address.
-func (w *wizard) readIPAddress() net.IP {
+// returning it if it's convertible to an IP address. The reason for keeping
+// the user input format instead of returning a Go net.IP is to match with
+// weird formats used by ethstats, which compares IPs textually, not by value.
+func (w *wizard) readIPAddress() string {
 	for {
 		// Read the IP address from the user
 		fmt.Printf("> ")
@@ -312,14 +314,13 @@ func (w *wizard) readIPAddress() net.IP {
 			log.Crit("Failed to read user input", "err", err)
 		}
 		if text = strings.TrimSpace(text); text == "" {
-			return nil
+			return ""
 		}
 		// Make sure it looks ok and return it if so
-		ip := net.ParseIP(text)
-		if ip == nil {
+		if ip := net.ParseIP(text); ip == nil {
 			log.Error("Invalid IP address, please retry")
 			continue
 		}
-		return ip
+		return text
 	}
 }
diff --git a/cmd/puppeth/wizard_ethstats.go b/cmd/puppeth/wizard_ethstats.go
index 504d8fd9cb..8bfa1d6e52 100644
--- a/cmd/puppeth/wizard_ethstats.go
+++ b/cmd/puppeth/wizard_ethstats.go
@@ -18,6 +18,7 @@ package main
 
 import (
 	"fmt"
+	"sort"
 
 	"github.com/ethereum/go-ethereum/log"
 )
@@ -64,17 +65,37 @@ func (w *wizard) deployEthstats() {
 	fmt.Println()
 	fmt.Printf("Keep existing IP %v blacklist (y/n)? (default = yes)\n", infos.banned)
 	if w.readDefaultString("y") != "y" {
-		infos.banned = nil
-
+		// The user might want to clear the entire list, although generally probably not
 		fmt.Println()
-		fmt.Println("Which IP addresses should be blacklisted?")
+		fmt.Printf("Clear out blacklist and start over (y/n)? (default = no)\n")
+		if w.readDefaultString("n") != "n" {
+			infos.banned = nil
+		}
+		// Offer the user to explicitly add/remove certain IP addresses
+		fmt.Println()
+		fmt.Println("Which additional IP addresses should be blacklisted?")
 		for {
-			if ip := w.readIPAddress(); ip != nil {
-				infos.banned = append(infos.banned, ip.String())
+			if ip := w.readIPAddress(); ip != "" {
+				infos.banned = append(infos.banned, ip)
 				continue
 			}
 			break
 		}
+		fmt.Println()
+		fmt.Println("Which IP addresses should not be blacklisted?")
+		for {
+			if ip := w.readIPAddress(); ip != "" {
+				for i, addr := range infos.banned {
+					if ip == addr {
+						infos.banned = append(infos.banned[:i], infos.banned[i+1:]...)
+						break
+					}
+				}
+				continue
+			}
+			break
+		}
+		sort.Strings(infos.banned)
 	}
 	// Try to deploy the ethstats server on the host
 	trusted := make([]string, 0, len(w.servers))
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index a62b4940ba..bfef619f6c 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -31,6 +31,8 @@ import (
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/consensus/clique"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/state"
@@ -1086,17 +1088,22 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (chain *core.BlockChain, chai
 	var err error
 	chainDb = MakeChainDatabase(ctx, stack)
 
-	engine := ethash.NewFaker()
-	if !ctx.GlobalBool(FakePoWFlag.Name) {
-		engine = ethash.New(
-			stack.ResolvePath(eth.DefaultConfig.EthashCacheDir), eth.DefaultConfig.EthashCachesInMem, eth.DefaultConfig.EthashCachesOnDisk,
-			stack.ResolvePath(eth.DefaultConfig.EthashDatasetDir), eth.DefaultConfig.EthashDatasetsInMem, eth.DefaultConfig.EthashDatasetsOnDisk,
-		)
-	}
 	config, _, err := core.SetupGenesisBlock(chainDb, MakeGenesis(ctx))
 	if err != nil {
 		Fatalf("%v", err)
 	}
+	var engine consensus.Engine
+	if config.Clique != nil {
+		engine = clique.New(config.Clique, chainDb)
+	} else {
+		engine = ethash.NewFaker()
+		if !ctx.GlobalBool(FakePoWFlag.Name) {
+			engine = ethash.New(
+				stack.ResolvePath(eth.DefaultConfig.EthashCacheDir), eth.DefaultConfig.EthashCachesInMem, eth.DefaultConfig.EthashCachesOnDisk,
+				stack.ResolvePath(eth.DefaultConfig.EthashDatasetDir), eth.DefaultConfig.EthashDatasetsInMem, eth.DefaultConfig.EthashDatasetsOnDisk,
+			)
+		}
+	}
 	vmcfg := vm.Config{EnablePreimageRecording: ctx.GlobalBool(VMEnableDebugFlag.Name)}
 	chain, err = core.NewBlockChain(chainDb, config, engine, vmcfg)
 	if err != nil {
diff --git a/consensus/ethash/algorithm.go b/consensus/ethash/algorithm.go
index a737bc636b..76f19252fa 100644
--- a/consensus/ethash/algorithm.go
+++ b/consensus/ethash/algorithm.go
@@ -102,7 +102,7 @@ func generateCache(dest []uint32, epoch uint64, seed []byte) {
 	header.Cap *= 4
 	cache := *(*[]byte)(unsafe.Pointer(&header))
 
-	// Calculate the number of thoretical rows (we'll store in one buffer nonetheless)
+	// Calculate the number of theoretical rows (we'll store in one buffer nonetheless)
 	size := uint64(len(cache))
 	rows := int(size) / hashBytes
 
@@ -187,7 +187,7 @@ func fnvHash(mix []uint32, data []uint32) {
 // generateDatasetItem combines data from 256 pseudorandomly selected cache nodes,
 // and hashes that to compute a single dataset node.
 func generateDatasetItem(cache []uint32, index uint32, keccak512 hasher) []byte {
-	// Calculate the number of thoretical rows (we use one buffer nonetheless)
+	// Calculate the number of theoretical rows (we use one buffer nonetheless)
 	rows := uint32(len(cache) / hashWords)
 
 	// Initialize the mix
@@ -287,7 +287,7 @@ func generateDataset(dest []uint32, epoch uint64, cache []uint32) {
 // hashimoto aggregates data from the full dataset in order to produce our final
 // value for a particular header hash and nonce.
 func hashimoto(hash []byte, nonce uint64, size uint64, lookup func(index uint32) []uint32) ([]byte, []byte) {
-	// Calculate the number of thoretical rows (we use one buffer nonetheless)
+	// Calculate the number of theoretical rows (we use one buffer nonetheless)
 	rows := uint32(size / mixBytes)
 
 	// Combine header+nonce into a 64 byte seed
diff --git a/core/types/transaction_test.go b/core/types/transaction_test.go
index 30ecb84ddb..82d74e3b34 100644
--- a/core/types/transaction_test.go
+++ b/core/types/transaction_test.go
@@ -147,12 +147,12 @@ func TestTransactionPriceNonceSort(t *testing.T) {
 	txset := NewTransactionsByPriceAndNonce(signer, groups)
 
 	txs := Transactions{}
-	for {
-		if tx := txset.Peek(); tx != nil {
-			txs = append(txs, tx)
-			txset.Shift()
-		}
-		break
+	for tx := txset.Peek(); tx != nil; tx = txset.Peek() {
+		txs = append(txs, tx)
+		txset.Shift()
+	}
+	if len(txs) != 25*25 {
+		t.Errorf("expected %d transactions, found %d", 25*25, len(txs))
 	}
 	for i, txi := range txs {
 		fromi, _ := Sender(signer, txi)
diff --git a/eth/downloader/fakepeer.go b/eth/downloader/fakepeer.go
new file mode 100644
index 0000000000..ebdb9c3342
--- /dev/null
+++ b/eth/downloader/fakepeer.go
@@ -0,0 +1,160 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package downloader
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb"
+)
+
+// FakePeer is a mock downloader peer that operates on a local database instance
+// instead of being an actual live node. It's useful for testing and to implement
+// sync commands from an xisting local database.
+type FakePeer struct {
+	id string
+	db ethdb.Database
+	hc *core.HeaderChain
+	dl *Downloader
+}
+
+// NewFakePeer creates a new mock downloader peer with the given data sources.
+func NewFakePeer(id string, db ethdb.Database, hc *core.HeaderChain, dl *Downloader) *FakePeer {
+	return &FakePeer{id: id, db: db, hc: hc, dl: dl}
+}
+
+// Head implements downloader.Peer, returning the current head hash and number
+// of the best known header.
+func (p *FakePeer) Head() (common.Hash, *big.Int) {
+	header := p.hc.CurrentHeader()
+	return header.Hash(), header.Number
+}
+
+// RequestHeadersByHash implements downloader.Peer, returning a batch of headers
+// defined by the origin hash and the associaed query parameters.
+func (p *FakePeer) RequestHeadersByHash(hash common.Hash, amount int, skip int, reverse bool) error {
+	var (
+		headers []*types.Header
+		unknown bool
+	)
+	for !unknown && len(headers) < amount {
+		origin := p.hc.GetHeaderByHash(hash)
+		if origin == nil {
+			break
+		}
+		number := origin.Number.Uint64()
+		headers = append(headers, origin)
+		if reverse {
+			for i := 0; i < int(skip)+1; i++ {
+				if header := p.hc.GetHeader(hash, number); header != nil {
+					hash = header.ParentHash
+					number--
+				} else {
+					unknown = true
+					break
+				}
+			}
+		} else {
+			var (
+				current = origin.Number.Uint64()
+				next    = current + uint64(skip) + 1
+			)
+			if header := p.hc.GetHeaderByNumber(next); header != nil {
+				if p.hc.GetBlockHashesFromHash(header.Hash(), uint64(skip+1))[skip] == hash {
+					hash = header.Hash()
+				} else {
+					unknown = true
+				}
+			} else {
+				unknown = true
+			}
+		}
+	}
+	p.dl.DeliverHeaders(p.id, headers)
+	return nil
+}
+
+// RequestHeadersByNumber implements downloader.Peer, returning a batch of headers
+// defined by the origin number and the associaed query parameters.
+func (p *FakePeer) RequestHeadersByNumber(number uint64, amount int, skip int, reverse bool) error {
+	var (
+		headers []*types.Header
+		unknown bool
+	)
+	for !unknown && len(headers) < amount {
+		origin := p.hc.GetHeaderByNumber(number)
+		if origin == nil {
+			break
+		}
+		if reverse {
+			if number >= uint64(skip+1) {
+				number -= uint64(skip + 1)
+			} else {
+				unknown = true
+			}
+		} else {
+			number += uint64(skip + 1)
+		}
+		headers = append(headers, origin)
+	}
+	p.dl.DeliverHeaders(p.id, headers)
+	return nil
+}
+
+// RequestBodies implements downloader.Peer, returning a batch of block bodies
+// corresponding to the specified block hashes.
+func (p *FakePeer) RequestBodies(hashes []common.Hash) error {
+	var (
+		txs    [][]*types.Transaction
+		uncles [][]*types.Header
+	)
+	for _, hash := range hashes {
+		block := core.GetBlock(p.db, hash, p.hc.GetBlockNumber(hash))
+
+		txs = append(txs, block.Transactions())
+		uncles = append(uncles, block.Uncles())
+	}
+	p.dl.DeliverBodies(p.id, txs, uncles)
+	return nil
+}
+
+// RequestReceipts implements downloader.Peer, returning a batch of transaction
+// receipts corresponding to the specified block hashes.
+func (p *FakePeer) RequestReceipts(hashes []common.Hash) error {
+	var receipts [][]*types.Receipt
+	for _, hash := range hashes {
+		receipts = append(receipts, core.GetBlockReceipts(p.db, hash, p.hc.GetBlockNumber(hash)))
+	}
+	p.dl.DeliverReceipts(p.id, receipts)
+	return nil
+}
+
+// RequestNodeData implements downloader.Peer, returning a batch of state trie
+// nodes corresponding to the specified trie hashes.
+func (p *FakePeer) RequestNodeData(hashes []common.Hash) error {
+	var data [][]byte
+	for _, hash := range hashes {
+		if entry, err := p.db.Get(hash.Bytes()); err == nil {
+			data = append(data, entry)
+		}
+	}
+	p.dl.DeliverNodeData(p.id, data)
+	return nil
+}
diff --git a/event/event.go b/event/event.go
index d3e84f0f7f..20d20d1f57 100644
--- a/event/event.go
+++ b/event/event.go
@@ -56,7 +56,7 @@ func (mux *TypeMux) Subscribe(types ...interface{}) *TypeMuxSubscription {
 	defer mux.mutex.Unlock()
 	if mux.stopped {
 		// set the status to closed so that calling Unsubscribe after this
-		// call will short curuit
+		// call will short circuit.
 		sub.closed = true
 		close(sub.postC)
 	} else {
diff --git a/miner/remote_agent.go b/miner/remote_agent.go
index aac7ce8655..287e7530c3 100644
--- a/miner/remote_agent.go
+++ b/miner/remote_agent.go
@@ -163,7 +163,7 @@ func (a *RemoteAgent) SubmitWork(nonce types.BlockNonce, mixDigest, hash common.
 }
 
 // loop monitors mining events on the work and quit channels, updating the internal
-// state of the rmeote miner until a termination is requested.
+// state of the remote miner until a termination is requested.
 //
 // Note, the reason the work and quit channels are passed as parameters is because
 // RemoteAgent.Start() constantly recreates these channels, so the loop code cannot
diff --git a/trie/trie_test.go b/trie/trie_test.go
index 1c90950703..1e28c3bc48 100644
--- a/trie/trie_test.go
+++ b/trie/trie_test.go
@@ -22,6 +22,7 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"math/big"
 	"math/rand"
 	"os"
 	"reflect"
@@ -30,7 +31,9 @@ import (
 
 	"github.com/davecgh/go-spew/spew"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 func init() {
@@ -505,8 +508,6 @@ func BenchmarkGet(b *testing.B)      { benchGet(b, false) }
 func BenchmarkGetDB(b *testing.B)    { benchGet(b, true) }
 func BenchmarkUpdateBE(b *testing.B) { benchUpdate(b, binary.BigEndian) }
 func BenchmarkUpdateLE(b *testing.B) { benchUpdate(b, binary.LittleEndian) }
-func BenchmarkHashBE(b *testing.B)   { benchHash(b, binary.BigEndian) }
-func BenchmarkHashLE(b *testing.B)   { benchHash(b, binary.LittleEndian) }
 
 const benchElemCount = 20000
 
@@ -549,18 +550,39 @@ func benchUpdate(b *testing.B, e binary.ByteOrder) *Trie {
 	return trie
 }
 
-func benchHash(b *testing.B, e binary.ByteOrder) {
-	trie := newEmpty()
-	k := make([]byte, 32)
-	for i := 0; i < benchElemCount; i++ {
-		e.PutUint64(k, uint64(i))
-		trie.Update(k, k)
-	}
+// Benchmarks the trie hashing. Since the trie caches the result of any operation,
+// we cannot use b.N as the number of hashing rouns, since all rounds apart from
+// the first one will be NOOP. As such, we'll use b.N as the number of account to
+// insert into the trie before measuring the hashing.
+func BenchmarkHash(b *testing.B) {
+	// Make the random benchmark deterministic
+	random := rand.New(rand.NewSource(0))
 
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		trie.Hash()
+	// Create a realistic account trie to hash
+	addresses := make([][20]byte, b.N)
+	for i := 0; i < len(addresses); i++ {
+		for j := 0; j < len(addresses[i]); j++ {
+			addresses[i][j] = byte(random.Intn(256))
+		}
 	}
+	accounts := make([][]byte, len(addresses))
+	for i := 0; i < len(accounts); i++ {
+		var (
+			nonce   = uint64(random.Int63())
+			balance = new(big.Int).Rand(random, new(big.Int).Exp(common.Big2, common.Big256, nil))
+			root    = emptyRoot
+			code    = crypto.Keccak256(nil)
+		)
+		accounts[i], _ = rlp.EncodeToBytes([]interface{}{nonce, balance, root, code})
+	}
+	// Insert the accounts into the trie and hash it
+	trie := newEmpty()
+	for i := 0; i < len(addresses); i++ {
+		trie.Update(crypto.Keccak256(addresses[i][:]), accounts[i])
+	}
+	b.ResetTimer()
+	b.ReportAllocs()
+	trie.Hash()
 }
 
 func tempDB() (string, Database) {