diff --git a/Cargo.lock b/Cargo.lock
index 19fe95318..a6fa12b3a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1270,7 +1270,7 @@ dependencies = [
 [[package]]
 name = "parity-ui-precompiled"
 version = "1.4.0"
-source = "git+https://github.com/ethcore/js-precompiled.git#d6232885df4b43c91291d31c769e48f107246d73"
+source = "git+https://github.com/ethcore/js-precompiled.git#7700411d2b0ba1372e0d6cf72a84ecf873a181f3"
 dependencies = [
  "parity-dapps-glue 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/ethcore/res/ethereum/tests b/ethcore/res/ethereum/tests
index d509c7593..e8f4624b7 160000
--- a/ethcore/res/ethereum/tests
+++ b/ethcore/res/ethereum/tests
@@ -1 +1 @@
-Subproject commit d509c75936ec6cbba683ee1916aa0bca436bc376
+Subproject commit e8f4624b7f1a15c63674eecf577c7ab76c3b16be
diff --git a/ethcore/src/client/client.rs b/ethcore/src/client/client.rs
index 9a6ac7e7f..394d69a92 100644
--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@@ -1297,7 +1297,7 @@ impl BlockChainClient for Client {
 		}
 	}
 
-	fn signing_network_id(&self) -> Option<u8> {
+	fn signing_network_id(&self) -> Option<u64> {
 		self.engine.signing_network_id(&self.latest_env_info())
 	}
 
diff --git a/ethcore/src/client/test_client.rs b/ethcore/src/client/test_client.rs
index 04e1c782d..b93205762 100644
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@@ -666,7 +666,7 @@ impl BlockChainClient for TestBlockChainClient {
 		self.miner.pending_transactions(self.chain_info().best_block_number)
 	}
 
-	fn signing_network_id(&self) -> Option<u8> { None }
+	fn signing_network_id(&self) -> Option<u64> { None }
 
 	fn mode(&self) -> Mode { Mode::Active }
 
diff --git a/ethcore/src/client/traits.rs b/ethcore/src/client/traits.rs
index 2a5c887ba..e6a71357e 100644
--- a/ethcore/src/client/traits.rs
+++ b/ethcore/src/client/traits.rs
@@ -240,7 +240,7 @@ pub trait BlockChainClient : Sync + Send {
 	}
 
 	/// Get the preferred network ID to sign on
-	fn signing_network_id(&self) -> Option<u8>;
+	fn signing_network_id(&self) -> Option<u64>;
 
 	/// Get the mode.
 	fn mode(&self) -> Mode;
diff --git a/ethcore/src/engines/mod.rs b/ethcore/src/engines/mod.rs
index f157cc505..29ede0495 100644
--- a/ethcore/src/engines/mod.rs
+++ b/ethcore/src/engines/mod.rs
@@ -149,7 +149,7 @@ pub trait Engine : Sync + Send {
 	fn verify_transaction(&self, _t: &SignedTransaction, _header: &Header) -> Result<(), Error> { Ok(()) }
 
 	/// The network ID that transactions should be signed with.
-	fn signing_network_id(&self, _env_info: &EnvInfo) -> Option<u8> { None }
+	fn signing_network_id(&self, _env_info: &EnvInfo) -> Option<u64> { None }
 
 	/// Verify the seal of a block. This is an auxilliary method that actually just calls other `verify_` methods
 	/// to get the job done. By default it must pass `verify_basic` and `verify_block_unordered`. If more or fewer
diff --git a/ethcore/src/ethereum/ethash.rs b/ethcore/src/ethereum/ethash.rs
index ca69ebff0..f5cf5d4f0 100644
--- a/ethcore/src/ethereum/ethash.rs
+++ b/ethcore/src/ethereum/ethash.rs
@@ -165,9 +165,9 @@ impl Engine for Ethash {
 		}
 	}
 
-	fn signing_network_id(&self, env_info: &EnvInfo) -> Option<u8> {
-		if env_info.number >= self.ethash_params.eip155_transition && self.params().network_id < 127 {
-			Some(self.params().network_id as u8)
+	fn signing_network_id(&self, env_info: &EnvInfo) -> Option<u64> {
+		if env_info.number >= self.ethash_params.eip155_transition {
+			Some(self.params().network_id)
 		} else {
 			None
 		}
@@ -316,7 +316,7 @@ impl Engine for Ethash {
 		}
 
 		if let Some(n) = t.network_id() {
-			if header.number() < self.ethash_params.eip155_transition || n as usize != self.params().network_id {
+			if header.number() < self.ethash_params.eip155_transition || n != self.params().network_id {
 				return Err(TransactionError::InvalidNetworkId.into())
 			}
 		}
diff --git a/ethcore/src/spec/spec.rs b/ethcore/src/spec/spec.rs
index f8ecf2402..cd501cbdf 100644
--- a/ethcore/src/spec/spec.rs
+++ b/ethcore/src/spec/spec.rs
@@ -37,7 +37,7 @@ pub struct CommonParams {
 	/// Maximum size of extra data.
 	pub maximum_extra_data_size: usize,
 	/// Network id.
-	pub network_id: usize,
+	pub network_id: u64,
 	/// Main subprotocol name.
 	pub subprotocol_name: String,
 	/// Minimum gas limit.
@@ -164,7 +164,7 @@ impl Spec {
 	pub fn nodes(&self) -> &[String] { &self.nodes }
 
 	/// Get the configured Network ID.
-	pub fn network_id(&self) -> usize { self.params.network_id }
+	pub fn network_id(&self) -> u64 { self.params.network_id }
 
 	/// Get the configured subprotocol name.
 	pub fn subprotocol_name(&self) -> String { self.params.subprotocol_name.clone() }
diff --git a/ethcore/src/types/transaction.rs b/ethcore/src/types/transaction.rs
index 7dba4da53..29afb2226 100644
--- a/ethcore/src/types/transaction.rs
+++ b/ethcore/src/types/transaction.rs
@@ -72,7 +72,7 @@ pub struct Transaction {
 
 impl Transaction {
 	/// Append object with a without signature into RLP stream
-	pub fn rlp_append_unsigned_transaction(&self, s: &mut RlpStream, network_id: Option<u8>) {
+	pub fn rlp_append_unsigned_transaction(&self, s: &mut RlpStream, network_id: Option<u64>) {
 		s.begin_list(if network_id.is_none() { 6 } else { 9 });
 		s.append(&self.nonce);
 		s.append(&self.gas_price);
@@ -140,26 +140,26 @@ impl From<ethjson::transaction::Transaction> for SignedTransaction {
 
 impl Transaction {
 	/// The message hash of the transaction.
-	pub fn hash(&self, network_id: Option<u8>) -> H256 {
+	pub fn hash(&self, network_id: Option<u64>) -> H256 {
 		let mut stream = RlpStream::new();
 		self.rlp_append_unsigned_transaction(&mut stream, network_id);
 		stream.out().sha3()
 	}
 
 	/// Signs the transaction as coming from `sender`.
-	pub fn sign(self, secret: &Secret, network_id: Option<u8>) -> SignedTransaction {
+	pub fn sign(self, secret: &Secret, network_id: Option<u64>) -> SignedTransaction {
 		let sig = ::ethkey::sign(secret, &self.hash(network_id))
 			.expect("data is valid and context has signing capabilities; qed");
 		self.with_signature(sig, network_id)
 	}
 
 	/// Signs the transaction with signature.
-	pub fn with_signature(self, sig: Signature, network_id: Option<u8>) -> SignedTransaction {
+	pub fn with_signature(self, sig: Signature, network_id: Option<u64>) -> SignedTransaction {
 		SignedTransaction {
 			unsigned: self,
 			r: sig.r().into(),
 			s: sig.s().into(),
-			v: sig.v() + if let Some(n) = network_id { 35 + n * 2 } else { 27 },
+			v: sig.v() as u64 + if let Some(n) = network_id { 35 + n * 2 } else { 27 },
 			hash: Cell::new(None),
 			sender: Cell::new(None),
 		}
@@ -211,7 +211,7 @@ pub struct SignedTransaction {
 	unsigned: Transaction,
 	/// The V field of the signature; the LS bit described which half of the curve our point falls
 	/// in. The MS bits describe which network this transaction is for. If 27/28, its for all networks.
-	v: u8,
+	v: u64,
 	/// The R field of the signature; helps describe the point on the curve.
 	r: U256,
 	/// The S field of the signature; helps describe the point on the curve.
@@ -302,10 +302,10 @@ impl SignedTransaction {
 	}
 
 	/// 0 if `v` would have been 27 under "Electrum" notation, 1 if 28 or 4 if invalid.
-	pub fn standard_v(&self) -> u8 { match self.v { v if v == 27 || v == 28 || v > 36 => (v - 1) % 2, _ => 4 } }
+	pub fn standard_v(&self) -> u8 { match self.v { v if v == 27 || v == 28 || v > 36 => ((v - 1) % 2) as u8, _ => 4 } }
 
 	/// The network ID, or `None` if this is a global transaction.
-	pub fn network_id(&self) -> Option<u8> {
+	pub fn network_id(&self) -> Option<u64> {
 		match self.v {
 			v if v > 36 => Some((v - 35) / 2),
 			_ => None,
diff --git a/js/package.json b/js/package.json
index 588a06e1b..5341cee31 100644
--- a/js/package.json
+++ b/js/package.json
@@ -1,6 +1,6 @@
 {
   "name": "parity.js",
-  "version": "0.2.90",
+  "version": "0.2.91",
   "main": "release/index.js",
   "jsnext:main": "src/index.js",
   "author": "Parity Team <admin@parity.io>",
diff --git a/parity/cli/mod.rs b/parity/cli/mod.rs
index d04989662..d7df05b89 100644
--- a/parity/cli/mod.rs
+++ b/parity/cli/mod.rs
@@ -48,7 +48,7 @@ usage! {
 		flag_testnet: bool,
 		flag_import_geth_keys: bool,
 		flag_datadir: Option<String>,
-		flag_networkid: Option<usize>,
+		flag_networkid: Option<u64>,
 		flag_peers: Option<u16>,
 		flag_nodekey: Option<String>,
 		flag_nodiscover: bool,
@@ -122,7 +122,7 @@ usage! {
 			or |c: &Config| otry!(c.network).nat.clone(),
 		flag_allow_ips: String = "all",
 			or |c: &Config| otry!(c.network).allow_ips.clone(),
-		flag_network_id: Option<usize> = None,
+		flag_network_id: Option<u64> = None,
 			or |c: &Config| otry!(c.network).id.clone().map(Some),
 		flag_bootnodes: Option<String> = None,
 			or |c: &Config| otry!(c.network).bootnodes.clone().map(|vec| Some(vec.join(","))),
@@ -328,7 +328,7 @@ struct Network {
 	max_pending_peers: Option<u16>,
 	nat: Option<String>,
 	allow_ips: Option<String>,
-	id: Option<usize>,
+	id: Option<u64>,
 	bootnodes: Option<Vec<String>>,
 	discovery: Option<bool>,
 	node_key: Option<String>,
diff --git a/parity/configuration.rs b/parity/configuration.rs
index c4a54f747..37c699521 100644
--- a/parity/configuration.rs
+++ b/parity/configuration.rs
@@ -527,7 +527,7 @@ impl Configuration {
 		Ok(ret)
 	}
 
-	fn network_id(&self) -> Option<usize> {
+	fn network_id(&self) -> Option<u64> {
 		self.args.flag_network_id.or(self.args.flag_networkid)
 	}
 
diff --git a/parity/run.rs b/parity/run.rs
index f23981d27..2509d1347 100644
--- a/parity/run.rs
+++ b/parity/run.rs
@@ -70,7 +70,7 @@ pub struct RunCmd {
 	pub http_conf: HttpConfiguration,
 	pub ipc_conf: IpcConfiguration,
 	pub net_conf: NetworkConfiguration,
-	pub network_id: Option<usize>,
+	pub network_id: Option<u64>,
 	pub warp_sync: bool,
 	pub acc_conf: AccountsConfig,
 	pub gas_pricer: GasPricerConfig,
diff --git a/rpc/src/v1/tests/helpers/sync_provider.rs b/rpc/src/v1/tests/helpers/sync_provider.rs
index 24be33417..8800d926a 100644
--- a/rpc/src/v1/tests/helpers/sync_provider.rs
+++ b/rpc/src/v1/tests/helpers/sync_provider.rs
@@ -23,7 +23,7 @@ use ethsync::{SyncProvider, SyncStatus, SyncState, PeerInfo, TransactionStats};
 /// TestSyncProvider config.
 pub struct Config {
 	/// Protocol version.
-	pub network_id: usize,
+	pub network_id: u64,
 	/// Number of peers.
 	pub num_peers: usize,
 }
diff --git a/sync/src/api.rs b/sync/src/api.rs
index b27713203..79e5806e1 100644
--- a/sync/src/api.rs
+++ b/sync/src/api.rs
@@ -47,7 +47,7 @@ pub struct SyncConfig {
 	/// Enable ancient block download.
 	pub download_old_blocks: bool,
 	/// Network ID
-	pub network_id: usize,
+	pub network_id: u64,
 	/// Main "eth" subprotocol name.
 	pub subprotocol_name: [u8; 3],
 	/// Fork block to check
diff --git a/sync/src/chain.rs b/sync/src/chain.rs
index f2d6929d9..319a7f611 100644
--- a/sync/src/chain.rs
+++ b/sync/src/chain.rs
@@ -194,7 +194,7 @@ pub struct SyncStatus {
 	/// Syncing protocol version. That's the maximum protocol version we connect to.
 	pub protocol_version: u8,
 	/// The underlying p2p network version.
-	pub network_id: usize,
+	pub network_id: u64,
 	/// `BlockChain` height for the moment the sync started.
 	pub start_block_number: BlockNumber,
 	/// Last fully downloaded and imported block number (if any).
@@ -275,7 +275,7 @@ struct PeerInfo {
 	/// Peer chain genesis hash
 	genesis: H256,
 	/// Peer network id
-	network_id: usize,
+	network_id: u64,
 	/// Peer best block hash
 	latest_hash: H256,
 	/// Peer total difficulty if known
@@ -343,7 +343,7 @@ pub struct ChainSync {
 	/// Last propagated block number
 	last_sent_block_number: BlockNumber,
 	/// Network ID
-	network_id: usize,
+	network_id: u64,
 	/// Optional fork block to check
 	fork_block: Option<(BlockNumber, H256)>,
 	/// Snapshot downloader.