diff --git a/CMakeLists.txt b/CMakeLists.txt
index 89d3c167a..3330977aa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,7 +43,7 @@ option(GUI "Build GUI components (AlethZero, Mix)" ON)
 option(TESTS "Build the tests." ON)
 option(NOBOOST "No use of boost macros in test functions" OFF)
 option(EVMJIT "Build just-in-time compiler for EVM code (requires LLVM)" OFF)
-option(ETHASHCL "Build in support for GPU mining via OpenCL" OFF)
+option(ETHASHCL "Build in support for GPU mining via OpenCL" ON)
 option(JSCONSOLE "Build in javascript console" ON)
 
 # propagates CMake configuration options to the compiler
diff --git a/libethcore/BlockInfo.h b/libethcore/BlockInfo.h
index c310b3dd9..cf3a9820e 100644
--- a/libethcore/BlockInfo.h
+++ b/libethcore/BlockInfo.h
@@ -75,7 +75,7 @@ DEV_SIMPLE_EXCEPTION(NoHashRecorded);
  * The default constructor creates an empty object, which can be tested against with the boolean
  * conversion operator.
  */
-struct BlockInfo
+class BlockInfo
 {
 	friend class BlockChain;
 public:
@@ -209,7 +209,7 @@ public:
 	void populateFromParent(BlockHeaderPolished const& _parent)
 	{
 		noteDirty();
-		BlockInfo::parentHash = _parent.hash();
+		BlockInfo::m_parentHash = _parent.hash();
 		BlockInfo::populateFromParent(_parent);
 		BlockInfoSub::populateFromParent(_parent);
 	}
diff --git a/libethcore/Ethash.cpp b/libethcore/Ethash.cpp
index ee483aa8b..09c6cbe19 100644
--- a/libethcore/Ethash.cpp
+++ b/libethcore/Ethash.cpp
@@ -196,7 +196,7 @@ public:
 	static unsigned instances() { return s_numInstances > 0 ? s_numInstances : std::thread::hardware_concurrency(); }
 	static std::string platformInfo();
 	static void listDevices() {}
-	static bool configureGPU(unsigned, unsigned, unsigned, unsigned, unsigned, bool, unsigned,  boost::optional<uint64_t>) { return false; }
+	static bool configureGPU(unsigned, unsigned, unsigned, unsigned, unsigned, bool, unsigned, uint64_t) { return false; }
 	static void setNumInstances(unsigned _instances) { s_numInstances = std::min<unsigned>(_instances, std::thread::hardware_concurrency()); }
 
 protected:
@@ -234,7 +234,7 @@ public:
 		unsigned _deviceId,
 		bool _allowCPU,
 		unsigned _extraGPUMemory,
-		boost::optional<uint64_t> _currentBlock
+		uint64_t _currentBlock
 	);
 	static void setNumInstances(unsigned _instances) { s_numInstances = std::min<unsigned>(_instances, getNumDevices()); }
 
@@ -246,7 +246,7 @@ private:
 	void workLoop() override;
 	bool report(uint64_t _nonce);
 
-	using Miner::accumulateHashes;
+	using GenericMiner<EthashProofOfWork>::accumulateHashes;
 
 	EthashCLHook* m_hook = nullptr;
 	ethash_cl_miner* m_miner = nullptr;
@@ -448,7 +448,7 @@ std::string EthashCPUMiner::platformInfo()
 class EthashCLHook: public ethash_cl_miner::search_hook
 {
 public:
-	EthashCLHook(Ethash::GPUMiner* _owner): m_owner(_owner) {}
+	EthashCLHook(EthashGPUMiner* _owner): m_owner(_owner) {}
 	EthashCLHook(EthashCLHook const&) = delete;
 
 	void abort()
@@ -511,7 +511,7 @@ unsigned EthashGPUMiner::s_deviceId = 0;
 unsigned EthashGPUMiner::s_numInstances = 0;
 
 EthashGPUMiner::EthashGPUMiner(ConstructionInfo const& _ci):
-	Miner(_ci),
+	GenericMiner<EthashProofOfWork>(_ci),
 	Worker("gpuminer" + toString(index())),
 	m_hook(new EthashCLHook(this))
 {
@@ -527,7 +527,7 @@ EthashGPUMiner::~EthashGPUMiner()
 bool EthashGPUMiner::report(uint64_t _nonce)
 {
 	Nonce n = (Nonce)(u64)_nonce;
-	Result r = EthashAux::eval(work().seedHash, work().headerHash, n);
+	EthashProofOfWork::Result r = EthashAux::eval(work().seedHash, work().headerHash, n);
 	if (r.value < work().boundary)
 		return submitProof(Solution{n, r.mixHash});
 	return false;
diff --git a/libethereum/BlockChain.cpp b/libethereum/BlockChain.cpp
index 8a654fa51..2b6cb25c2 100644
--- a/libethereum/BlockChain.cpp
+++ b/libethereum/BlockChain.cpp
@@ -849,7 +849,7 @@ void BlockChain::rescue(OverlayDB& _db)
 			u = m;
 	}
 	cout << "  lowest is " << l << endl;
-	for (;; --l)
+	for (; l > 0; --l)
 	{
 		h256 h = numberHash(l);
 		cout << "Checking validity of " << l << " (" << h << ")..." << flush;
diff --git a/libethereum/BlockChain.h b/libethereum/BlockChain.h
index 2269407b6..d60be548a 100644
--- a/libethereum/BlockChain.h
+++ b/libethereum/BlockChain.h
@@ -395,7 +395,12 @@ public:
 			BlockHeader h(_block, (_ir & ImportRequirements::ValidSeal) ? Strictness::CheckEverything : Strictness::QuickNonce);
 			h.verifyInternals(_block);
 			if ((_ir & ImportRequirements::Parent) != 0)
-				h.verifyParent(header(h.parentHash()));
+			{
+				bytes parentHeader(headerData(h.parentHash()));
+				if (parentHeader.empty())
+					BOOST_THROW_EXCEPTION(InvalidParentHash());
+				h.verifyParent(typename Sealer::BlockHeader(parentHeader, IgnoreSeal, h.parentHash(), HeaderData));
+			}
 			res.info = static_cast<BlockInfo&>(h);
 		}
 		catch (Exception& ex)
diff --git a/libethereum/Client.h b/libethereum/Client.h
index 33d7558cd..896444176 100644
--- a/libethereum/Client.h
+++ b/libethereum/Client.h
@@ -346,7 +346,7 @@ public:
 	{
 		m_sealEngine = std::shared_ptr<SealEngineFace>(Ethash::createSealEngine());
 		m_sealEngine->onSealGenerated([=](bytes const& header){
-			return this->submitSealed(header);
+			this->submitSealed(header);
 		});
 		init(_host, _dbPath, _forceAction, _networkId);
 	}
diff --git a/libp2p/Host.cpp b/libp2p/Host.cpp
index d57741e61..46e0efe95 100644
--- a/libp2p/Host.cpp
+++ b/libp2p/Host.cpp
@@ -399,43 +399,42 @@ void Host::runAcceptor()
 		auto socket = make_shared<RLPXSocket>(new bi::tcp::socket(m_ioService));
 		m_tcp4Acceptor.async_accept(socket->ref(), [=](boost::system::error_code ec)
 		{
-			if (peerCount() > 9 * m_idealPeerCount)
+			m_accepting = false;
+			if (ec || !m_run)
+			{
+				socket->close();
+				return;
+			}
+			if (peerCount() > Ingress * m_idealPeerCount)
 			{
-				clog(NetConnect) << "Dropping incoming connect due to maximum peer count (9 * ideal peer count): " << socket->remoteEndpoint();
+				clog(NetConnect) << "Dropping incoming connect due to maximum peer count (" << Ingress << " * ideal peer count): " << socket->remoteEndpoint();
 				socket->close();
 				if (ec.value() < 1)
 					runAcceptor();
 				return;
 			}
 			
-			// if no error code
 			bool success = false;
-			if (!ec)
+			try
 			{
-				try
-				{
-					// incoming connection; we don't yet know nodeid
-					auto handshake = make_shared<RLPXHandshake>(this, socket);
-					m_connecting.push_back(handshake);
-					handshake->start();
-					success = true;
-				}
-				catch (Exception const& _e)
-				{
-					clog(NetWarn) << "ERROR: " << diagnostic_information(_e);
-				}
-				catch (std::exception const& _e)
-				{
-					clog(NetWarn) << "ERROR: " << _e.what();
-				}
+				// incoming connection; we don't yet know nodeid
+				auto handshake = make_shared<RLPXHandshake>(this, socket);
+				m_connecting.push_back(handshake);
+				handshake->start();
+				success = true;
+			}
+			catch (Exception const& _e)
+			{
+				clog(NetWarn) << "ERROR: " << diagnostic_information(_e);
+			}
+			catch (std::exception const& _e)
+			{
+				clog(NetWarn) << "ERROR: " << _e.what();
 			}
 
 			if (!success)
 				socket->ref().close();
-			
-			m_accepting = false;
-			if (ec.value() < 1)
-				runAcceptor();
+			runAcceptor();
 		});
 	}
 }
@@ -627,7 +626,7 @@ void Host::run(boost::system::error_code const&)
 	m_nodeTable->processEvents();
 
 	// cleanup zombies
-	DEV_GUARDED(x_connecting);
+	DEV_GUARDED(x_connecting)
 		m_connecting.remove_if([](std::weak_ptr<RLPXHandshake> h){ return h.expired(); });
 	DEV_GUARDED(x_timers)
 		m_timers.remove_if([](std::shared_ptr<boost::asio::deadline_timer> t)
diff --git a/libp2p/Host.h b/libp2p/Host.h
index 17e98f8f6..0fe6da5f9 100644
--- a/libp2p/Host.h
+++ b/libp2p/Host.h
@@ -212,7 +212,7 @@ protected:
 	void restoreNetwork(bytesConstRef _b);
 
 private:
-	enum PeerSlotRatio { Egress = 2, Ingress = 9 };
+	enum PeerSlotRatio { Egress = 1, Ingress = 4 };
 	
 	bool havePeerSession(NodeId const& _id) { return !!peerSession(_id); }
 
diff --git a/test/TestHelper.cpp b/test/TestHelper.cpp
index c29788b9f..aec72285c 100644
--- a/test/TestHelper.cpp
+++ b/test/TestHelper.cpp
@@ -63,38 +63,23 @@ void connectClients(Client& c1, Client& c2)
 
 void mine(State& s, BlockChain const& _bc)
 {
+	std::unique_ptr<SealEngineFace> sealer(Ethash::createSealEngine());
 	s.commitToMine(_bc);
-	GenericFarm<EthashProofOfWork> f;
-	bool completed = false;
-	Ethash::BlockHeader header(s.info);
-	f.onSolutionFound([&](EthashProofOfWork::Solution sol)
-	{
-			header.m_mixHash = sol.mixHash;
-			header.m_nonce = sol.nonce;
-			RLPStream ret;
-			header.streamRLP(ret);
-			s.sealBlock(ret);
-			return true;
-	});
-	f.setWork(s.info());
-	f.startCPU();
-	while (!completed)
-		this_thread::sleep_for(chrono::milliseconds(20));
-}
-
-void mine(BlockInfo& _bi)
-{
-	GenericFarm<EthashProofOfWork> f;
-	bool completed = false;
-	f.onSolutionFound([&](EthashProofOfWork::Solution sol)
-	{
-		_bi.proof = sol;
-		return completed = true;
-	});
-	f.setWork(_bi);
-	f.startCPU();
-	while (!completed)
-		this_thread::sleep_for(chrono::milliseconds(20));
+	Notified<bytes> sealed;
+	sealer->onSealGenerated([&](bytes const& sealedHeader){ sealed = sealedHeader; });
+	sealer->generateSeal(s.info());
+	sealed.waitNot({});
+	s.sealBlock(sealed);
+}
+
+void mine(Ethash::BlockHeader& _bi)
+{
+	std::unique_ptr<SealEngineFace> sealer(Ethash::createSealEngine());
+	Notified<bytes> sealed;
+	sealer->onSealGenerated([&](bytes const& sealedHeader){ sealed = sealedHeader; });
+	sealer->generateSeal(_bi);
+	sealed.waitNot({});
+	_bi = Ethash::BlockHeader(sealed);
 }
 
 }
@@ -158,13 +143,24 @@ void ImportTest::importEnv(json_spirit::mObject& _o)
 	assert(_o.count("currentCoinbase") > 0);
 	assert(_o.count("currentNumber") > 0);
 
-	m_environment.currentBlock.parentHash() = h256(_o["previousHash"].get_str());
-	m_environment.currentBlock.number = toInt(_o["currentNumber"]);
-	m_environment.currentBlock.gasLimit = toInt(_o["currentGasLimit"]);
-	m_environment.currentBlock.difficulty = toInt(_o["currentDifficulty"]);
-	m_environment.currentBlock.timestamp() = toInt(_o["currentTimestamp"]);
-	m_environment.currentBlock.coinbaseAddress() = Address(_o["currentCoinbase"].get_str());
-
+	RLPStream rlpStream;
+	rlpStream.appendList(BlockInfo::BasicFields);
+
+	rlpStream << h256(_o["previousHash"].get_str());
+	rlpStream << EmptyListSHA3;
+	rlpStream << Address(_o["currentCoinbase"].get_str());
+	rlpStream << h256(); // stateRoot
+	rlpStream << EmptyTrie; // transactionTrie
+	rlpStream << EmptyTrie; // receiptTrie
+	rlpStream << LogBloom(); // bloom
+	rlpStream << toInt(_o["currentDifficulty"]);
+	rlpStream << toInt(_o["currentNumber"]);
+	rlpStream << toInt(_o["currentGasLimit"]);
+	rlpStream << 0; //gasUsed
+	rlpStream << toInt(_o["currentTimestamp"]);
+	rlpStream << std::string(); //extra data
+
+	m_environment.currentBlock = BlockInfo(rlpStream.out(), CheckEverything, h256{}, HeaderData);
 	m_statePre.m_previousBlock = m_environment.previousBlock;
 	m_statePre.m_currentBlock = m_environment.currentBlock;
 }
@@ -824,6 +820,43 @@ LastHashes lastHashes(u256 _currentBlockNumber)
 	return ret;
 }
 
+dev::eth::Ethash::BlockHeader constructHeader(
+	h256 const& _parentHash,
+	h256 const& _sha3Uncles,
+	Address const& _coinbaseAddress,
+	h256 const& _stateRoot,
+	h256 const& _transactionsRoot,
+	h256 const& _receiptsRoot,
+	dev::eth::LogBloom const& _logBloom,
+	u256 const& _difficulty,
+	u256 const& _number,
+	u256 const& _gasLimit,
+	u256 const& _gasUsed,
+	u256 const& _timestamp,
+	bytes const& _extraData)
+{
+	RLPStream rlpStream;
+	rlpStream.appendList(Ethash::BlockHeader::Fields);
+
+	rlpStream << _parentHash << _sha3Uncles << _coinbaseAddress << _stateRoot << _transactionsRoot << _receiptsRoot << _logBloom
+		<< _difficulty << _number << _gasLimit << _gasUsed << _timestamp << _extraData << h256{} << Nonce{};
+
+	return Ethash::BlockHeader(rlpStream.out());
+}
+
+void updateEthashSeal(dev::eth::Ethash::BlockHeader& _header, h256 const& _mixHash, dev::eth::Nonce const& _nonce)
+{
+	RLPStream source;
+	_header.streamRLP(source);
+	RLP sourceRlp(source.out());
+	RLPStream header;
+	header.appendList(Ethash::BlockHeader::Fields);
+	for (size_t i = 0; i < BlockInfo::BasicFields; i++)
+		header << sourceRlp[i];
+
+	header << _mixHash << _nonce;
+	_header = Ethash::BlockHeader(header.out());
+}
 
 namespace
 {
diff --git a/test/TestHelper.h b/test/TestHelper.h
index 420278838..735535492 100644
--- a/test/TestHelper.h
+++ b/test/TestHelper.h
@@ -27,6 +27,7 @@
 #include <boost/filesystem.hpp>
 
 #include "JsonSpiritHeaders.h"
+#include <libethcore/Ethash.h>
 #include <libethereum/State.h>
 #include <libevm/ExtVMFace.h>
 #include <libtestutils/Common.h>
@@ -62,7 +63,7 @@ class State;
 void mine(Client& c, int numBlocks);
 void connectClients(Client& c1, Client& c2);
 void mine(State& _s, BlockChain const& _bc);
-void mine(BlockInfo& _bi);
+void mine(Ethash::BlockHeader& _bi);
 
 }
 
@@ -175,7 +176,21 @@ void checkOutput(bytes const& _output, json_spirit::mObject& _o);
 void checkStorage(std::map<u256, u256> _expectedStore, std::map<u256, u256> _resultStore, Address _expectedAddr);
 void checkLog(eth::LogEntries _resultLogs, eth::LogEntries _expectedLogs);
 void checkCallCreates(eth::Transactions _resultCallCreates, eth::Transactions _expectedCallCreates);
-
+dev::eth::Ethash::BlockHeader constructHeader(
+	h256 const& _parentHash,
+	h256 const& _sha3Uncles,
+	Address const& _coinbaseAddress,
+	h256 const& _stateRoot,
+	h256 const& _transactionsRoot,
+	h256 const& _receiptsRoot,
+	dev::eth::LogBloom const& _logBloom,
+	u256 const& _difficulty,
+	u256 const& _number,
+	u256 const& _gasLimit,
+	u256 const& _gasUsed,
+	u256 const& _timestamp,
+	bytes const& _extraData);
+void updateEthashSeal(dev::eth::Ethash::BlockHeader& _header, h256 const& _mixHash, dev::eth::Nonce const& _nonce);
 void executeTests(const std::string& _name, const std::string& _testPathAppendix, const boost::filesystem::path _pathToFiller, std::function<void(json_spirit::mValue&, bool)> doTests);
 void userDefinedTest(std::function<void(json_spirit::mValue&, bool)> doTests);
 RLPStream createRLPStreamFromTransactionFields(json_spirit::mObject& _tObj);
@@ -224,7 +239,7 @@ public:
 	bool inputLimits = false;
 	bool bigData = false;
 	bool wallet = false;
-	bool nonetwork = true;
+	bool nonetwork = false;
 	bool nodag = true;
 	/// @}
 
diff --git a/test/fuzzTesting/checkRandomStateTest.cpp b/test/fuzzTesting/checkRandomStateTest.cpp
index 01366cd4d..adbb953f3 100644
--- a/test/fuzzTesting/checkRandomStateTest.cpp
+++ b/test/fuzzTesting/checkRandomStateTest.cpp
@@ -87,7 +87,7 @@ bool doStateTest(mValue& _v)
 
 		try
 		{
-			output = theState.execute(lastHashes(importer.m_environment.currentBlock.number), importer.m_transaction).output;
+			output = theState.execute(lastHashes(importer.m_environment.currentBlock.number()), importer.m_transaction).output;
 		}
 		catch (Exception const& _e)
 		{
diff --git a/test/fuzzTesting/createRandomStateTest.cpp b/test/fuzzTesting/createRandomStateTest.cpp
index d533ac2da..be751f2b7 100644
--- a/test/fuzzTesting/createRandomStateTest.cpp
+++ b/test/fuzzTesting/createRandomStateTest.cpp
@@ -233,7 +233,7 @@ void doStateTests(json_spirit::mValue& _v)
 			eth::State theState = importer.m_statePre;
 			try
 			{
-				output = theState.execute(test::lastHashes(importer.m_environment.currentBlock.number), importer.m_transaction).output;
+				output = theState.execute(test::lastHashes(importer.m_environment.currentBlock.number()), importer.m_transaction).output;
 			}
 			catch (Exception const& _e)
 			{
diff --git a/test/libethcore/dagger.cpp b/test/libethcore/dagger.cpp
index c3cd75b0d..0e69793e2 100644
--- a/test/libethcore/dagger.cpp
+++ b/test/libethcore/dagger.cpp
@@ -54,7 +54,7 @@ BOOST_AUTO_TEST_CASE(basic_test)
 		cnote << i.first;
 		js::mObject& o = i.second.get_obj();
 		vector<pair<string, string>> ss;
-		Ethash::BlockHeader header(fromHex(o["header"].get_str()), CheckNothing);
+		Ethash::BlockHeader header(fromHex(o["header"].get_str()), CheckNothing, h256{}, HeaderData);
 		h256 headerHash(o["header_hash"].get_str());
 		Nonce nonce(o["nonce"].get_str());
 		BOOST_REQUIRE_EQUAL(headerHash, header.hashWithout());
diff --git a/test/libethereum/ClientBase.cpp b/test/libethereum/ClientBase.cpp
index f9d83e9c6..7c9b7197f 100644
--- a/test/libethereum/ClientBase.cpp
+++ b/test/libethereum/ClientBase.cpp
@@ -21,6 +21,7 @@
 
 #include <boost/test/unit_test.hpp>
 #include <libdevcore/CommonJS.h>
+#include <libtestutils/FixedClient.h>
 #include "../TestUtils.h"
 
 using namespace std;
@@ -139,7 +140,7 @@ BOOST_AUTO_TEST_CASE(blocks)
 				ETH_CHECK_EQUAL(expectedBlockInfoUncldeHash, _blockInfo.sha3Uncles());
 			};
 
-			Ethash::BlockHeader blockInfo(_client.bc().headerData(blockHash));
+			Ethash::BlockHeader blockInfo((static_cast<FixedClient&>(_client)).bc().headerData(blockHash));
 			compareBlockInfos(blockHeader, blockInfo);
 
 			// blockDetails
diff --git a/test/libethereum/blockchain.cpp b/test/libethereum/blockchain.cpp
index cf44dfd9f..764585520 100644
--- a/test/libethereum/blockchain.cpp
+++ b/test/libethereum/blockchain.cpp
@@ -37,16 +37,17 @@ namespace dev {  namespace test {
 typedef std::vector<bytes> uncleList;
 typedef std::pair<bytes, uncleList> blockSet;
 
-BlockInfo constructBlock(mObject& _o);
-bytes createBlockRLPFromFields(mObject& _tObj);
-RLPStream createFullBlockFromHeader(BlockInfo const& _bi, bytes const& _txs = RLPEmptyList, bytes const& _uncles = RLPEmptyList);
+using BlockHeader = Ethash::BlockHeader;
+
+BlockHeader constructBlock(mObject& _o, h256 const& _stateRoot = h256{});
+bytes createBlockRLPFromFields(mObject& _tObj, h256 const&  _stateRoot = h256{});
+RLPStream createFullBlockFromHeader(BlockHeader const& _bi, bytes const& _txs = RLPEmptyList, bytes const& _uncles = RLPEmptyList);
 
 mArray writeTransactionsToJson(Transactions const& txs);
-mObject writeBlockHeaderToJson(mObject& _o, BlockInfo const& _bi);
-void overwriteBlockHeader(BlockInfo& _current_BlockHeader, mObject& _blObj);
-BlockInfo constructBlock(mObject& _o);
-void updatePoW(BlockInfo& _bi);
-mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector<BlockInfo> const& _vBiBlocks, std::vector<blockSet> _blockSet);
+mObject writeBlockHeaderToJson(mObject& _o, BlockHeader const& _bi);
+void overwriteBlockHeader(BlockHeader& _current_BlockHeader, mObject& _blObj);
+void updatePoW(BlockHeader& _bi);
+mArray importUncles(mObject const& _blObj, vector<BlockHeader>& _vBiUncles, vector<BlockHeader> const& _vBiBlocks, std::vector<blockSet> _blockSet);
 
 void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 {
@@ -61,12 +62,12 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 
 		cerr << i.first << endl;
 		TBOOST_REQUIRE(o.count("genesisBlockHeader"));
-		BlockInfo biGenesisBlock = constructBlock(o["genesisBlockHeader"].get_obj());
 
 		TBOOST_REQUIRE(o.count("pre"));
 		ImportTest importer(o["pre"].get_obj());
 		TransientDirectory td_stateDB_tmp;
-		State trueState(OverlayDB(State::openDB(td_stateDB_tmp.path())), BaseState::Empty, biGenesisBlock.coinbaseAddress());
+		BlockHeader biGenesisBlock = constructBlock(o["genesisBlockHeader"].get_obj(), h256{});
+		State trueState(OverlayDB(State::openDB(td_stateDB_tmp.path(), h256{}, WithExisting::Kill)), BaseState::Empty, biGenesisBlock.coinbaseAddress());
 
 		//Imported blocks from the start
 		std::vector<blockSet> blockSets;
@@ -76,7 +77,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 		trueState.commit();
 
 		if (_fillin)
-			biGenesisBlock.stateRoot() = trueState.rootHash();
+			biGenesisBlock = constructBlock(o["genesisBlockHeader"].get_obj(), trueState.rootHash());
 		else
 			TBOOST_CHECK_MESSAGE((biGenesisBlock.stateRoot() == trueState.rootHash()), "root hash does not match");
 
@@ -96,7 +97,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 
 		// construct true blockchain
 		TransientDirectory td;
-		BlockChain trueBc(rlpGenesisBlock.out(), td.path(), WithExisting::Kill);
+		FullBlockChain<Ethash> trueBc(rlpGenesisBlock.out(), StateDefinition(), td.path(), WithExisting::Kill);
 
 		if (_fillin)
 		{
@@ -107,7 +108,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 			genesis.first = rlpGenesisBlock.out();
 			genesis.second = uncleList();
 			blockSets.push_back(genesis);
-			vector<BlockInfo> vBiBlocks;
+			vector<BlockHeader> vBiBlocks;
 			vBiBlocks.push_back(biGenesisBlock);
 
 			size_t importBlockNumber = 0;
@@ -124,8 +125,9 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 				vBiBlocks.push_back(biGenesisBlock);
 
 				TransientDirectory td_stateDB, td_bc;
-				BlockChain bc(rlpGenesisBlock.out(), td_bc.path(), WithExisting::Kill);
-				State state(OverlayDB(State::openDB(td_stateDB.path())), BaseState::Empty, biGenesisBlock.coinbaseAddress());
+				FullBlockChain<Ethash> bc(rlpGenesisBlock.out(), StateDefinition(), td_bc.path(), WithExisting::Kill);
+				State state(OverlayDB(State::openDB(td_stateDB.path(), h256{}, WithExisting::Kill)), BaseState::Empty);
+				trueState.setAddress(biGenesisBlock.coinbaseAddress());
 				importer.importState(o["pre"].get_obj(), state);
 				state.commit();
 
@@ -134,12 +136,12 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					BlockQueue uncleQueue;
 					uncleList uncles = blockSets.at(i).second;
 					for (size_t j = 0; j < uncles.size(); j++)
-						uncleQueue.import(&uncles.at(j), bc);
+						uncleQueue.import(&uncles.at(j), false);
 
 					const bytes block = blockSets.at(i).first;
 					bc.sync(uncleQueue, state.db(), 4);
 					bc.attemptImport(block, state.db());
-					vBiBlocks.push_back(BlockInfo(block));
+					vBiBlocks.push_back(BlockHeader(block));
 					state.sync(bc);
 				}
 
@@ -156,7 +158,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 				}
 
 				//get uncles
-				vector<BlockInfo> vBiUncles;
+				vector<BlockHeader> vBiUncles;
 				blObj["uncleHeaders"] = importUncles(blObj, vBiUncles, vBiBlocks, blockSets);
 
 				BlockQueue uncleBlockQueue;
@@ -167,7 +169,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					RLPStream uncle = createFullBlockFromHeader(vBiUncles.at(i));
 					try
 					{
-						uncleBlockQueue.import(&uncle.out(), bc);
+						uncleBlockQueue.import(&uncle.out(), false);
 						uncleBlockQueueList.push_back(uncle.out());
 						// wait until block is verified
 						this_thread::sleep_for(chrono::seconds(1));
@@ -205,14 +207,14 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					txList.push_back(txi);
 				blObj["transactions"] = writeTransactionsToJson(txList);
 
-				BlockInfo current_BlockHeader = state.info();
+				BlockHeader current_BlockHeader = state.info();
 
 				RLPStream uncleStream;
 				uncleStream.appendList(vBiUncles.size());
 				for (unsigned i = 0; i < vBiUncles.size(); ++i)
 				{
 					RLPStream uncleRlp;
-					vBiUncles[i].streamRLP(uncleRlp, WithNonce);
+					vBiUncles[i].streamRLP(uncleRlp);
 					uncleStream.appendRaw(uncleRlp.out());
 				}
 
@@ -225,7 +227,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 				if (vBiUncles.size())
 				{
 					// update unclehash in case of invalid uncles
-					current_BlockHeader.sha3Uncles() = sha3(uncleStream.out());
+					current_BlockHeader.setSha3Uncles(sha3(uncleStream.out()));
 					updatePoW(current_BlockHeader);
 				}
 
@@ -330,7 +332,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					blockRLP = importByteArray(blObj["rlp"].get_str());
 					trueState.sync(trueBc);
 					trueBc.import(blockRLP, trueState.db());
-					if (trueBc.info() != BlockInfo(blockRLP))
+					if (trueBc.info() != BlockHeader(blockRLP))
 						importedAndBest  = false;
 					trueState.sync(trueBc);
 				}
@@ -363,17 +365,17 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 				TBOOST_REQUIRE(blObj.count("blockHeader"));
 
 				mObject tObj = blObj["blockHeader"].get_obj();
-				BlockInfo blockHeaderFromFields;
+				BlockHeader blockHeaderFromFields;
 				const bytes c_rlpBytesBlockHeader = createBlockRLPFromFields(tObj);
 				const RLP c_blockHeaderRLP(c_rlpBytesBlockHeader);
-				blockHeaderFromFields.populateFromHeader(c_blockHeaderRLP, IgnoreNonce);
+				blockHeaderFromFields.populateFromHeader(c_blockHeaderRLP, IgnoreSeal);
 
-				BlockInfo blockFromRlp = trueBc.info();
+				BlockHeader blockFromRlp(trueBc.header());
 
 				if (importedAndBest)
 				{
 					//Check the fields restored from RLP to original fields
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.headerHash(WithNonce) == blockFromRlp.headerHash(WithNonce)), "hash in given RLP not matching the block hash!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.headerHash(WithProof) == blockFromRlp.headerHash(WithProof)), "hash in given RLP not matching the block hash!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.parentHash() == blockFromRlp.parentHash()), "parentHash in given RLP not matching the block parentHash!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.sha3Uncles() == blockFromRlp.sha3Uncles()), "sha3Uncles in given RLP not matching the block sha3Uncles!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.coinbaseAddress() == blockFromRlp.coinbaseAddress()),"coinbaseAddress in given RLP not matching the block coinbaseAddress!");
@@ -381,14 +383,14 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.transactionsRoot() == blockFromRlp.transactionsRoot()), "transactionsRoot in given RLP not matching the block transactionsRoot!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.receiptsRoot() == blockFromRlp.receiptsRoot()), "receiptsRoot in given RLP not matching the block receiptsRoot!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.logBloom() == blockFromRlp.logBloom()), "logBloom in given RLP not matching the block logBloom!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.difficulty == blockFromRlp.difficulty), "difficulty in given RLP not matching the block difficulty!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.number == blockFromRlp.number), "number in given RLP not matching the block number!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.gasLimit == blockFromRlp.gasLimit),"gasLimit in given RLP not matching the block gasLimit!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.gasUsed == blockFromRlp.gasUsed), "gasUsed in given RLP not matching the block gasUsed!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.difficulty() == blockFromRlp.difficulty()), "difficulty in given RLP not matching the block difficulty!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.number() == blockFromRlp.number()), "number in given RLP not matching the block number!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.gasLimit() == blockFromRlp.gasLimit()),"gasLimit in given RLP not matching the block gasLimit!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.gasUsed() == blockFromRlp.gasUsed()), "gasUsed in given RLP not matching the block gasUsed!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.timestamp() == blockFromRlp.timestamp()), "timestamp in given RLP not matching the block timestamp!");
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.extraData() == blockFromRlp.extraData()), "extraData in given RLP not matching the block extraData!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.mixHash == blockFromRlp.mixHash), "mixHash in given RLP not matching the block mixHash!");
-					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.nonce == blockFromRlp.nonce), "nonce in given RLP not matching the block nonce!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.mixHash() == blockFromRlp.mixHash()), "mixHash in given RLP not matching the block mixHash!");
+					TBOOST_CHECK_MESSAGE((blockHeaderFromFields.nonce() == blockFromRlp.nonce()), "nonce in given RLP not matching the block nonce!");
 
 					TBOOST_CHECK_MESSAGE((blockHeaderFromFields == blockFromRlp), "However, blockHeaderFromFields != blockFromRlp!");
 
@@ -454,7 +456,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 					// check uncle list
 
 					// uncles from uncle list field
-					vector<BlockInfo> uBlHsFromField;
+					vector<BlockHeader> uBlHsFromField;
 					if (blObj["uncleHeaders"].type() != json_spirit::null_type)
 						for (auto const& uBlHeaderObj: blObj["uncleHeaders"].get_array())
 						{
@@ -462,7 +464,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 							TBOOST_REQUIRE((uBlH.size() == 16));
 							bytes uncleRLP = createBlockRLPFromFields(uBlH);
 							const RLP c_uRLP(uncleRLP);
-							BlockInfo uncleBlockHeader;
+							BlockHeader uncleBlockHeader;
 							try
 							{
 								uncleBlockHeader.populateFromHeader(c_uRLP);
@@ -475,10 +477,10 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 						}
 
 					// uncles from block RLP
-					vector<BlockInfo> uBlHsFromRlp;
+					vector<BlockHeader> uBlHsFromRlp;
 					for	(auto const& uRLP: root[2])
 					{
-						BlockInfo uBl;
+						BlockHeader uBl;
 						uBl.populateFromHeader(uRLP);
 						uBlHsFromRlp.push_back(uBl);
 					}
@@ -499,7 +501,7 @@ void doBlockchainTests(json_spirit::mValue& _v, bool _fillin)
 
 // helping functions
 
-mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector<BlockInfo> const& _vBiBlocks, std::vector<blockSet> _blockSet)
+mArray importUncles(mObject const& _blObj, vector<BlockHeader>& _vBiUncles, vector<BlockHeader> const& _vBiBlocks, std::vector<blockSet> _blockSet)
 {
 	// write uncle list
 	mArray aUncleList;
@@ -521,7 +523,7 @@ mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector
 		{
 			size_t number = (size_t)toInt(uncleHeaderObj["sameAsBlock"]);
 			uncleHeaderObj.erase("sameAsBlock");
-			BlockInfo currentUncle = _vBiBlocks[number];
+			BlockHeader currentUncle = _vBiBlocks[number];
 			writeBlockHeaderToJson(uncleHeaderObj, currentUncle);
 			aUncleList.push_back(uncleHeaderObj);
 			_vBiUncles.push_back(currentUncle);
@@ -532,7 +534,7 @@ mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector
 		if (uncleHeaderObj.count("sameAsPreviousBlockUncle"))
 		{
 			bytes uncleRLP = _blockSet[(size_t)toInt(uncleHeaderObj["sameAsPreviousBlockUncle"])].second[0];
-			BlockInfo uncleHeader(uncleRLP);
+			BlockHeader uncleHeader(uncleRLP);
 			writeBlockHeaderToJson(uncleHeaderObj, uncleHeader);
 			aUncleList.push_back(uncleHeaderObj);
 
@@ -548,15 +550,15 @@ mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector
 			uncleHeaderObj.erase("overwriteAndRedoPoW");
 		}
 
-		BlockInfo uncleBlockFromFields = constructBlock(uncleHeaderObj);
+		BlockHeader uncleBlockFromFields = constructBlock(uncleHeaderObj);
 
 		// make uncle header valid
-		uncleBlockFromFields.timestamp() = (u256)time(0);
-		cnote << "uncle block n = " << toString(uncleBlockFromFields.number);
+		uncleBlockFromFields.setTimestamp((u256)time(0));
+		cnote << "uncle block n = " << toString(uncleBlockFromFields.number());
 		if (_vBiBlocks.size() > 2)
 		{
-			if (uncleBlockFromFields.number - 1 < _vBiBlocks.size())
-				uncleBlockFromFields.populateFromParent(_vBiBlocks[(size_t)uncleBlockFromFields.number - 1]);
+			if (uncleBlockFromFields.number() - 1 < _vBiBlocks.size())
+				uncleBlockFromFields.populateFromParent(_vBiBlocks[(size_t)uncleBlockFromFields.number() - 1]);
 			else
 				uncleBlockFromFields.populateFromParent(_vBiBlocks[_vBiBlocks.size() - 2]);
 		}
@@ -565,29 +567,32 @@ mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector
 
 		if (overwrite != "false")
 		{
-			uncleBlockFromFields.difficulty = overwrite == "difficulty" ? toInt(uncleHeaderObj["difficulty"]) : uncleBlockFromFields.difficulty;
-			uncleBlockFromFields.gasLimit = overwrite == "gasLimit" ? toInt(uncleHeaderObj["gasLimit"]) : uncleBlockFromFields.gasLimit;
-			uncleBlockFromFields.gasUsed = overwrite == "gasUsed" ? toInt(uncleHeaderObj["gasUsed"]) : uncleBlockFromFields.gasUsed;
-			uncleBlockFromFields.parentHash() = overwrite == "parentHash" ? h256(uncleHeaderObj["parentHash"].get_str()) : uncleBlockFromFields.parentHash();
-			uncleBlockFromFields.stateRoot() = overwrite == "stateRoot" ? h256(uncleHeaderObj["stateRoot"].get_str()) : uncleBlockFromFields.stateRoot();
+			uncleBlockFromFields = constructHeader(
+				overwrite == "parentHash" ? h256(uncleHeaderObj["parentHash"].get_str()) : uncleBlockFromFields.parentHash(),
+				uncleBlockFromFields.sha3Uncles(),
+				uncleBlockFromFields.coinbaseAddress(),
+				overwrite == "stateRoot" ? h256(uncleHeaderObj["stateRoot"].get_str()) : uncleBlockFromFields.stateRoot(),
+				uncleBlockFromFields.transactionsRoot(),
+				uncleBlockFromFields.receiptsRoot(),
+				uncleBlockFromFields.logBloom(),
+				overwrite == "difficulty" ? toInt(uncleHeaderObj["difficulty"]) : overwrite == "timestamp" ? uncleBlockFromFields.calculateDifficulty(_vBiBlocks[(size_t)uncleBlockFromFields.number() - 1]) : uncleBlockFromFields.difficulty(),
+				uncleBlockFromFields.number(),
+				overwrite == "gasLimit" ? toInt(uncleHeaderObj["gasLimit"]) : uncleBlockFromFields.gasLimit(),
+				overwrite == "gasUsed" ? toInt(uncleHeaderObj["gasUsed"]) : uncleBlockFromFields.gasUsed(),
+				overwrite == "timestamp" ? toInt(uncleHeaderObj["timestamp"]) : uncleBlockFromFields.timestamp(),
+				uncleBlockFromFields.extraData());
 
 			if (overwrite == "parentHashIsBlocksParent")
 				uncleBlockFromFields.populateFromParent(_vBiBlocks[_vBiBlocks.size() - 1]);
-
-			if (overwrite == "timestamp")
-			{
-				uncleBlockFromFields.timestamp() = toInt(uncleHeaderObj["timestamp"]);
-				uncleBlockFromFields.difficulty = uncleBlockFromFields.calculateDifficulty(_vBiBlocks[(size_t)uncleBlockFromFields.number - 1]);
-			}
 		}
 
 		updatePoW(uncleBlockFromFields);
 
 		if (overwrite == "nonce")
-			uncleBlockFromFields.nonce = Nonce(uncleHeaderObj["nonce"].get_str());
+			updateEthashSeal(uncleBlockFromFields, uncleBlockFromFields.mixHash(), Nonce(uncleHeaderObj["nonce"].get_str()));
 
 		if (overwrite == "mixHash")
-			uncleBlockFromFields.mixHash = h256(uncleHeaderObj["mixHash"].get_str());
+			updateEthashSeal(uncleBlockFromFields, h256(uncleHeaderObj["mixHash"].get_str()), uncleBlockFromFields.nonce());
 
 		writeBlockHeaderToJson(uncleHeaderObj, uncleBlockFromFields);
 
@@ -600,7 +605,7 @@ mArray importUncles(mObject const& _blObj, vector<BlockInfo>& _vBiUncles, vector
 	return aUncleList;
 }
 
-bytes createBlockRLPFromFields(mObject& _tObj)
+bytes createBlockRLPFromFields(mObject& _tObj, h256 const& _stateRoot)
 {
 	RLPStream rlpStream;
 	rlpStream.appendList(_tObj.count("hash") > 0 ? (_tObj.size() - 1) : _tObj.size());
@@ -614,7 +619,9 @@ bytes createBlockRLPFromFields(mObject& _tObj)
 	if (_tObj.count("coinbase"))
 		rlpStream << importByteArray(_tObj["coinbase"].get_str());
 
-	if (_tObj.count("stateRoot"))
+	if (_stateRoot)
+		rlpStream << _stateRoot;
+	else if (_tObj.count("stateRoot"))
 		rlpStream << importByteArray(_tObj["stateRoot"].get_str());
 
 	if (_tObj.count("transactionsTrie"))
@@ -653,47 +660,35 @@ bytes createBlockRLPFromFields(mObject& _tObj)
 	return rlpStream.out();
 }
 
-void overwriteBlockHeader(BlockInfo& _header, mObject& _blObj)
+void overwriteBlockHeader(BlockHeader& _header, mObject& _blObj)
 {
 	auto ho = _blObj["blockHeader"].get_obj();
 	if (ho.size() != 14)
 	{
-		BlockInfo tmp = _header;
-		if (ho.count("parentHash"))
-			tmp.parentHash() = h256(ho["parentHash"].get_str());
-		if (ho.count("uncleHash"))
-			tmp.sha3Uncles() = h256(ho["uncleHash"].get_str());
-		if (ho.count("coinbase"))
-			tmp.coinbaseAddress() = Address(ho["coinbase"].get_str());
-		if (ho.count("stateRoot"))
-			tmp.stateRoot() = h256(ho["stateRoot"].get_str());
-		if (ho.count("transactionsTrie"))
-			tmp.transactionsRoot() = h256(ho["transactionsTrie"].get_str());
-		if (ho.count("receiptTrie"))
-			tmp.receiptsRoot() = h256(ho["receiptTrie"].get_str());
-		if (ho.count("bloom"))
-			tmp.logBloom() = LogBloom(ho["bloom"].get_str());
-		if (ho.count("difficulty"))
-			tmp.difficulty = toInt(ho["difficulty"]);
-		if (ho.count("number"))
-			tmp.number = toInt(ho["number"]);
-		if (ho.count("gasLimit"))
-			tmp.gasLimit = toInt(ho["gasLimit"]);
-		if (ho.count("gasUsed"))
-			tmp.gasUsed = toInt(ho["gasUsed"]);
-		if (ho.count("timestamp"))
-			tmp.timestamp() = toInt(ho["timestamp"]);
-		if (ho.count("extraData"))
-			tmp.extraData() = importByteArray(ho["extraData"].get_str());
+		BlockHeader tmp = constructHeader(
+			ho.count("parentHash") ? h256(ho["parentHash"].get_str()) : h256{},
+			ho.count("uncleHash") ? h256(ho["uncleHash"].get_str()) : EmptyListSHA3,
+			ho.count("coinbase") ? Address(ho["coinbase"].get_str()) : Address{},
+			ho.count("stateRoot") ? h256(ho["stateRoot"].get_str()): h256{},
+			ho.count("transactionsTrie") ? h256(ho["transactionsTrie"].get_str()) : EmptyTrie,
+			ho.count("receiptTrie") ? h256(ho["receiptTrie"].get_str()) : EmptyTrie,
+			ho.count("bloom") ? LogBloom(ho["bloom"].get_str()) : LogBloom{},
+			ho.count("difficulty") ? toInt(ho["difficulty"]) : u256(0),
+			ho.count("number") ? toInt(ho["number"]) : u256(0),
+			ho.count("gasLimit") ? toInt(ho["gasLimit"]) : u256(0),
+			ho.count("gasUsed") ? toInt(ho["gasUsed"]) : u256(0),
+			ho.count("timestamp") ? toInt(ho["timestamp"]) : u256(0),
+			ho.count("extraData") ? importByteArray(ho["extraData"].get_str()) : bytes{});
 
 		// find new valid nonce
-		if (tmp != _header && tmp.difficulty)
+		if (static_cast<BlockInfo>(tmp) != static_cast<BlockInfo>(_header) && tmp.difficulty())
 			mine(tmp);
 
+
 		if (ho.count("mixHash"))
-			tmp.mixHash = h256(ho["mixHash"].get_str());
+			updateEthashSeal(tmp, h256(ho["mixHash"].get_str()), tmp.nonce());
 		if (ho.count("nonce"))
-			tmp.nonce = Nonce(ho["nonce"].get_str());
+			updateEthashSeal(tmp, tmp.mixHash(), Nonce(ho["nonce"].get_str()));
 
 		tmp.noteDirty();
 		_header = tmp;
@@ -703,19 +698,19 @@ void overwriteBlockHeader(BlockInfo& _header, mObject& _blObj)
 		// take the blockheader as is
 		const bytes c_blockRLP = createBlockRLPFromFields(ho);
 		const RLP c_bRLP(c_blockRLP);
-		_header.populateFromHeader(c_bRLP, IgnoreNonce);
+		_header.populateFromHeader(c_bRLP, IgnoreSeal);
 	}
 }
 
-BlockInfo constructBlock(mObject& _o)
+BlockHeader constructBlock(mObject& _o, h256 const& _stateRoot)
 {
-	BlockInfo ret;
+	BlockHeader ret;
 	try
 	{
 		// construct genesis block
-		const bytes c_blockRLP = createBlockRLPFromFields(_o);
+		const bytes c_blockRLP = createBlockRLPFromFields(_o, _stateRoot);
 		const RLP c_bRLP(c_blockRLP);
-		ret.populateFromHeader(c_bRLP, IgnoreNonce);
+		ret.populateFromHeader(c_bRLP, IgnoreSeal);
 	}
 	catch (Exception const& _e)
 	{
@@ -732,7 +727,7 @@ BlockInfo constructBlock(mObject& _o)
 	return ret;
 }
 
-void updatePoW(BlockInfo& _bi)
+void updatePoW(BlockHeader& _bi)
 {
 	mine(_bi);
 	_bi.noteDirty();
@@ -749,7 +744,7 @@ mArray writeTransactionsToJson(Transactions const& txs)
 	return txArray;
 }
 
-mObject writeBlockHeaderToJson(mObject& _o, BlockInfo const& _bi)
+mObject writeBlockHeaderToJson(mObject& _o, BlockHeader const& _bi)
 {
 	_o["parentHash"] = toString(_bi.parentHash());
 	_o["uncleHash"] = toString(_bi.sha3Uncles());
@@ -758,22 +753,22 @@ mObject writeBlockHeaderToJson(mObject& _o, BlockInfo const& _bi)
 	_o["transactionsTrie"] = toString(_bi.transactionsRoot());
 	_o["receiptTrie"] = toString(_bi.receiptsRoot());
 	_o["bloom"] = toString(_bi.logBloom());
-	_o["difficulty"] = toCompactHex(_bi.difficulty, HexPrefix::Add, 1);
+	_o["difficulty"] = toCompactHex(_bi.difficulty(), HexPrefix::Add, 1);
 	_o["number"] = toCompactHex(_bi.number(), HexPrefix::Add, 1);
-	_o["gasLimit"] = toCompactHex(_bi.gasLimit, HexPrefix::Add, 1);
-	_o["gasUsed"] = toCompactHex(_bi.gasUsed, HexPrefix::Add, 1);
+	_o["gasLimit"] = toCompactHex(_bi.gasLimit(), HexPrefix::Add, 1);
+	_o["gasUsed"] = toCompactHex(_bi.gasUsed(), HexPrefix::Add, 1);
 	_o["timestamp"] = toCompactHex(_bi.timestamp(), HexPrefix::Add, 1);
 	_o["extraData"] = toHex(_bi.extraData(), 2, HexPrefix::Add);
-	_o["mixHash"] = toString(_bi.mixHash);
-	_o["nonce"] = toString(_bi.nonce);
+	_o["mixHash"] = toString(_bi.mixHash());
+	_o["nonce"] = toString(_bi.nonce());
 	_o["hash"] = toString(_bi.hash());
 	return _o;
 }
 
-RLPStream createFullBlockFromHeader(BlockInfo const& _bi, bytes const& _txs, bytes const& _uncles)
+RLPStream createFullBlockFromHeader(BlockHeader const& _bi, bytes const& _txs, bytes const& _uncles)
 {
 	RLPStream rlpStream;
-	_bi.streamRLP(rlpStream, WithNonce);
+	_bi.streamRLP(rlpStream, WithProof);
 
 	RLPStream ret(3);
 	ret.appendRaw(rlpStream.out());
diff --git a/test/libethereum/genesis.cpp b/test/libethereum/genesis.cpp
index 39997572f..a8bc852f0 100644
--- a/test/libethereum/genesis.cpp
+++ b/test/libethereum/genesis.cpp
@@ -62,7 +62,7 @@ BOOST_AUTO_TEST_CASE(genesis_tests)
 
 	BOOST_CHECK_EQUAL(CanonBlockChain<Ethash>::genesis().stateRoot(), h256(o["genesis_state_root"].get_str()));
 	BOOST_CHECK_EQUAL(toHex(CanonBlockChain<Ethash>::createGenesisBlock()), toHex(fromHex(o["genesis_rlp_hex"].get_str())));
-	BOOST_CHECK_EQUAL(Ethash::BlockHeader(CanonBlockChain<Ethash>::createGenesisBlock()).hashWithout(), h256(o["genesis_hash"].get_str()));
+	BOOST_CHECK_EQUAL(Ethash::BlockHeader(CanonBlockChain<Ethash>::createGenesisBlock()).hash(), h256(o["genesis_hash"].get_str()));
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/test/libethereum/state.cpp b/test/libethereum/state.cpp
index 45c2fa13e..825ed8b4b 100644
--- a/test/libethereum/state.cpp
+++ b/test/libethereum/state.cpp
@@ -63,7 +63,7 @@ void doStateTests(json_spirit::mValue& v, bool _fillin)
 		try
 		{
 			Listener::ExecTimeGuard guard{i.first};
-			output = theState.execute(lastHashes(importer.m_environment.currentBlock.number), importer.m_transaction).output;
+			output = theState.execute(lastHashes(importer.m_environment.currentBlock.number()), importer.m_transaction).output;
 		}
 		catch (Exception const& _e)
 		{
diff --git a/test/libevm/vm.cpp b/test/libevm/vm.cpp
index badabd70c..36f22734f 100644
--- a/test/libevm/vm.cpp
+++ b/test/libevm/vm.cpp
@@ -102,13 +102,26 @@ void FakeExtVM::importEnv(mObject& _o)
 	assert(_o.count("currentCoinbase") > 0);
 	assert(_o.count("currentNumber") > 0);
 
-	currentBlock.parentHash() = h256(_o["previousHash"].get_str());
-	currentBlock.number = toInt(_o["currentNumber"]);
-	lastHashes = test::lastHashes(currentBlock.number);
-	currentBlock.gasLimit = toInt(_o["currentGasLimit"]);
-	currentBlock.difficulty = toInt(_o["currentDifficulty"]);
-	currentBlock.timestamp = toInt(_o["currentTimestamp"]);
-	currentBlock.coinbaseAddress() = Address(_o["currentCoinbase"].get_str());
+
+	RLPStream rlpStream;
+	rlpStream.appendList(BlockInfo::BasicFields);
+
+	rlpStream << h256(_o["previousHash"].get_str());
+	rlpStream << EmptyListSHA3;
+	rlpStream << Address(_o["currentCoinbase"].get_str());
+	rlpStream << h256(); // stateRoot
+	rlpStream << EmptyTrie; // transactionTrie
+	rlpStream << EmptyTrie; // receiptTrie
+	rlpStream << LogBloom(); // bloom
+	rlpStream << toInt(_o["currentDifficulty"]);
+	rlpStream << toInt(_o["currentNumber"]);
+	rlpStream << toInt(_o["currentGasLimit"]);
+	rlpStream << 0; //gasUsed
+	rlpStream << toInt(_o["currentTimestamp"]);
+	rlpStream << std::string(); //extra data
+	currentBlock = BlockInfo(rlpStream.out(), CheckEverything, h256{}, HeaderData);
+
+	lastHashes = test::lastHashes(currentBlock.number());
 }
 
 mObject FakeExtVM::exportState()