diff --git a/ethcore/src/block.rs b/ethcore/src/block.rs
index f72c2f800..16d3e2216 100644
--- a/ethcore/src/block.rs
+++ b/ethcore/src/block.rs
@@ -182,6 +182,7 @@ impl<'x> OpenBlock<'x> {
 		r.block.base.header.set_author(author);
 		r.block.base.header.set_extra_data(extra_data);
 		r.block.base.header.set_timestamp_now(parent.timestamp());
+		r.block.base.header.set_parent_hash(parent.hash());
 
 		engine.populate_from_parent(&mut r.block.base.header, parent);
 		engine.on_new_block(&mut r.block);
@@ -308,10 +309,15 @@ impl ClosedBlock {
 	pub fn try_seal(self, engine: &Engine, seal: Vec<Bytes>) -> Result<SealedBlock, ClosedBlock> {
 		let mut s = self;
 		s.block.base.header.set_seal(seal);
-		match engine.verify_block_basic(&s.block.base.header, None).is_err() || engine.verify_block_unordered(&s.block.base.header, None).is_err() {
-			false => Err(s),
-			true => Ok(SealedBlock { block: s.block, uncle_bytes: s.uncle_bytes }),
+		if let Err(e) = engine.verify_block_basic(&s.block.base.header, None) {
+			debug!("Failed to try_seal: {:?}", e);
+			return Err(s);
 		}
+		if let Err(e) = engine.verify_block_unordered(&s.block.base.header, None) {
+			debug!("Failed to try_seal: {:?}", e);
+			return Err(s);
+		}
+		Ok(SealedBlock { block: s.block, uncle_bytes: s.uncle_bytes })
 	}
 
 	/// Drop this object and return the underlieing database.
diff --git a/ethcore/src/client.rs b/ethcore/src/client.rs
index c5aa987f6..de875348a 100644
--- a/ethcore/src/client.rs
+++ b/ethcore/src/client.rs
@@ -196,6 +196,8 @@ pub struct Client {
 
 	// for sealing...
 	sealing_block: Mutex<Option<ClosedBlock>>,
+	author: RwLock<Address>,
+	extra_data: RwLock<Bytes>,
 }
 
 const HISTORY: u64 = 1000;
@@ -233,6 +235,8 @@ impl Client {
 			import_lock: Mutex::new(()),
 			panic_handler: panic_handler,
 			sealing_block: Mutex::new(None),
+			author: RwLock::new(Address::new()),
+			extra_data: RwLock::new(Vec::new()),
 		}))
 	}
 
@@ -364,7 +368,7 @@ impl Client {
 		}
 
 		if self.chain_info().best_block_hash != original_best {
-			self.new_chain_head();
+			self.prepare_sealing();
 		}
 
 		imported
@@ -414,27 +418,55 @@ impl Client {
 		}
 	}
 
-	/// New chain head event.
-	pub fn new_chain_head(&self) {
+	/// Set the author that we will seal blocks as.
+	pub fn author(&self) -> Address {
+		self.author.read().unwrap().clone()
+	}
+
+	/// Set the author that we will seal blocks as.
+	pub fn set_author(&self, author: Address) {
+		*self.author.write().unwrap() = author;
+	}
+
+	/// Set the extra_data that we will seal blocks wuth.
+	pub fn extra_data(&self) -> Bytes {
+		self.extra_data.read().unwrap().clone()
+	}
+
+	/// Set the extra_data that we will seal blocks with.
+	pub fn set_extra_data(&self, extra_data: Bytes) {
+		*self.extra_data.write().unwrap() = extra_data;
+	}
+
+	/// New chain head event. Restart mining operation.
+	pub fn prepare_sealing(&self) {
 		let h = self.chain.read().unwrap().best_block_hash();
-		debug!("New best block: #{}: {}", self.chain.read().unwrap().best_block_number(), h);
 		let b = OpenBlock::new(
 			self.engine.deref().deref(),
 			self.state_db.lock().unwrap().clone(),
 			match self.chain.read().unwrap().block_header(&h) { Some(ref x) => x, None => {return;} },
-			self.build_last_hashes(h.clone()),
-			x!("0037a6b811ffeb6e072da21179d11b1406371c63"),
-			b"Parity".to_vec()
+			self.build_last_hashes(h),
+			self.author(),
+			self.extra_data()
 		);
+		// TODO: push uncles.
+		// TODO: push transactions.
 		let b = b.close();
-		debug!("Sealing: hash={}, diff={}, number={}", b.hash(), b.block().header().difficulty(), b.block().header().number());
+		trace!("Sealing: number={}, hash={}, diff={}", b.hash(), b.block().header().difficulty(), b.block().header().number());
+		debug!("Header: {:?}", b.block().header());
 		*self.sealing_block.lock().unwrap() = Some(b);
 	}
 
 	/// Grab the `ClosedBlock` that we want to be sealed. Comes as a mutex that you have to lock.
-	pub fn sealing_block(&self) -> &Mutex<Option<ClosedBlock>> { &self.sealing_block }
+	pub fn sealing_block(&self) -> &Mutex<Option<ClosedBlock>> {
+		if self.sealing_block.lock().unwrap().is_none() {
+			self.prepare_sealing();
+		}
+		&self.sealing_block
+	}
 
 	/// Submit `seal` as a valid solution for the header of `pow_hash`.
+	/// Will check the seal, but not actually insert the block into the chain.
 	pub fn submit_seal(&self, pow_hash: H256, seal: Vec<Bytes>) -> Result<(), Error> {
 		let mut maybe_b = self.sealing_block.lock().unwrap();
 		match *maybe_b {
diff --git a/ethcore/src/header.rs b/ethcore/src/header.rs
index 3db0be5ff..cc02d84db 100644
--- a/ethcore/src/header.rs
+++ b/ethcore/src/header.rs
@@ -102,10 +102,12 @@ impl Header {
 		Self::default()
 	}
 
-	/// Get the number field of the header.
-	pub fn number(&self) -> BlockNumber { self.number }
+	/// Get the parent_hash field of the header.
+	pub fn parent_hash(&self) -> &H256 { &self.parent_hash }
 	/// Get the timestamp field of the header.
 	pub fn timestamp(&self) -> u64 { self.timestamp }
+	/// Get the number field of the header.
+	pub fn number(&self) -> BlockNumber { self.number }
 	/// Get the author field of the header.
 	pub fn author(&self) -> &Address { &self.author }
 
@@ -127,11 +129,13 @@ impl Header {
 	// TODO: seal_at, set_seal_at &c.
 
 	/// Set the number field of the header.
-	pub fn set_number(&mut self, a: BlockNumber) { self.number = a; self.note_dirty(); }
+	pub fn set_parent_hash(&mut self, a: H256) { self.parent_hash = a; self.note_dirty(); }
 	/// Set the timestamp field of the header.
 	pub fn set_timestamp(&mut self, a: u64) { self.timestamp = a; self.note_dirty(); }
 	/// Set the timestamp field of the header to the current time.
 	pub fn set_timestamp_now(&mut self, but_later_than: u64) { self.timestamp = max(now_utc().to_timespec().sec as u64, but_later_than + 1); self.note_dirty(); }
+	/// Set the number field of the header.
+	pub fn set_number(&mut self, a: BlockNumber) { self.number = a; self.note_dirty(); }
 	/// Set the author field of the header.
 	pub fn set_author(&mut self, a: Address) { if a != self.author { self.author = a; self.note_dirty(); } }
 
diff --git a/parity/main.rs b/parity/main.rs
index 7241a2ac4..b991f36cd 100644
--- a/parity/main.rs
+++ b/parity/main.rs
@@ -85,6 +85,10 @@ Options:
   --jsonrpc-url URL        Specify URL for JSON-RPC API server [default: 127.0.0.1:8545].
   --jsonrpc-cors URL       Specify CORS header for JSON-RPC API responses [default: null].
 
+  --author ADDRESS         Specify the block author (aka "coinbase") address for sending block rewards
+                           from sealed blocks [default: 0037a6b811ffeb6e072da21179d11b1406371c63].
+  --extra-data STRING      Specify a custom extra-data for authored blocks, no more than 32 characters.
+
   -l --logging LOGGING     Specify the logging level.
   -v --version             Show information about version.
   -h --help                Show this screen.
@@ -114,6 +118,8 @@ struct Args {
 	flag_jsonrpc_cors: String,
 	flag_logging: Option<String>,
 	flag_version: bool,
+	flag_author: String,
+	flag_extra_data: Option<String>,
 }
 
 fn setup_log(init: &Option<String>) {
@@ -196,6 +202,18 @@ impl Configuration {
 		self.args.flag_db_path.replace("$HOME", env::home_dir().unwrap().to_str().unwrap())
 	}
 
+	fn author(&self) -> Address {
+		Address::from_str(&self.args.flag_author).unwrap_or_else(|_| die!("{}: Invalid address for --author. Must be 40 hex characters, without the 0x at the beginning.", self.args.flag_author))
+	}
+
+	fn extra_data(&self) -> Bytes {
+		match self.args.flag_extra_data {
+			Some(ref x) if x.len() <= 32 => x.as_bytes().to_owned(),
+			None => version_data(),
+			Some(ref x) => { die!("{}: Extra data must be at most 32 characters.", x); }
+		}
+	}
+
 	fn _keys_path(&self) -> String {
 		self.args.flag_keys_path.replace("$HOME", env::home_dir().unwrap().to_str().unwrap())
 	}
@@ -296,6 +314,8 @@ impl Configuration {
 		client_config.queue.max_mem_use = self.args.flag_queue_max_size;
 		let mut service = ClientService::start(client_config, spec, net_settings, &Path::new(&self.path())).unwrap();
 		let client = service.client().clone();
+		client.set_author(self.author());
+		client.set_extra_data(self.extra_data());
 
 		// Sync
 		let sync = EthSync::register(service.network(), sync_config, client);
diff --git a/rpc/src/v1/impls/eth.rs b/rpc/src/v1/impls/eth.rs
index 24ecbe5f1..a7583ddf7 100644
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@@ -236,12 +236,12 @@ impl Eth for EthClient {
 	}
 
 	fn submit_work(&self, params: Params) -> Result<Value, Error> {
-		// TODO: println! should be debug!
-		println!("Work submission: {:?}", params);
 		from_params::<(H64, H256, H256)>(params).and_then(|(nonce, pow_hash, mix_hash)| {
+//			trace!("Decoded: nonce={}, pow_hash={}, mix_hash={}", nonce, pow_hash, mix_hash);
 			let c = take_weak!(self.client);
 			let seal = vec![encode(&mix_hash).to_vec(), encode(&nonce).to_vec()];
-			to_value(&c.submit_seal(pow_hash, seal).is_ok())
+			let r = c.submit_seal(pow_hash, seal);
+			to_value(&r.is_ok())
 		})
 	}
 
diff --git a/util/src/misc.rs b/util/src/misc.rs
index 35e1f3a75..d9f52fd71 100644
--- a/util/src/misc.rs
+++ b/util/src/misc.rs
@@ -18,6 +18,7 @@
 
 use std::fs::File;
 use common::*;
+use rlp::{Stream, RlpStream};
 use target_info::Target;
 use rustc_version;
 
@@ -70,4 +71,18 @@ pub fn contents(name: &str) -> Result<Bytes, UtilError> {
 /// Get the standard version string for this software.
 pub fn version() -> String {
 	format!("Parity//v{}-{}-{}/{}-{}-{}/rustc{}", env!("CARGO_PKG_VERSION"), short_sha(), commit_date().replace("-", ""), Target::arch(), Target::os(), Target::env(), rustc_version::version())
+}
+
+/// Get the standard version data for this software.
+pub fn version_data() -> Bytes {
+	let mut s = RlpStream::new_list(4);
+	let v =
+		(u32::from_str(env!("CARGO_PKG_VERSION_MAJOR")).unwrap() << 16) +
+		(u32::from_str(env!("CARGO_PKG_VERSION_MINOR")).unwrap() << 8) +
+		u32::from_str(env!("CARGO_PKG_VERSION_PATCH")).unwrap();
+	s.append(&v);
+	s.append(&"Parity");
+	s.append(&format!("rustc{}", rustc_version::version()));
+	s.append(&Target::os());
+	s.out()
 }
\ No newline at end of file