diff --git a/ethcore/src/block.rs b/ethcore/src/block.rs
index eb9d66124..582b8669a 100644
--- a/ethcore/src/block.rs
+++ b/ethcore/src/block.rs
@@ -404,7 +404,7 @@ mod tests {
 		let mut db_result = get_temp_journal_db();
 		let mut db = db_result.take();
 		engine.spec().ensure_db_good(&mut db);
-		let b = OpenBlock::new(engine.deref(), db, &genesis_header, vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(vec![]).unwrap();
+		let b = OpenBlock::new(engine.deref(), db, &genesis_header, vec![genesis_header.hash()], Address::zero(), vec![]).close().seal(&engine, vec![]).unwrap();
 		let orig_bytes = b.rlp_bytes();
 		let orig_db = b.drain();
 
diff --git a/ethcore/src/block_queue.rs b/ethcore/src/block_queue.rs
index 143f53647..490a17995 100644
--- a/ethcore/src/block_queue.rs
+++ b/ethcore/src/block_queue.rs
@@ -455,7 +455,7 @@ mod tests {
 		match duplicate_import {
 			Err(e) => {
 				match e {
-					ImportError::AlreadyQueued => {},
+					Error::Import(ImportError::AlreadyQueued) => {},
 					_ => { panic!("must return AlreadyQueued error"); }
 				}
 			}
diff --git a/ethcore/src/blockchain/blockchain.rs b/ethcore/src/blockchain/blockchain.rs
index 0aba36a8e..88a6504ac 100644
--- a/ethcore/src/blockchain/blockchain.rs
+++ b/ethcore/src/blockchain/blockchain.rs
@@ -473,6 +473,12 @@ impl BlockChain {
 		self.extras_db.write(batch).unwrap();
 	}
 
+	/// Given a block's `parent`, find every block header which represents a valid uncle.
+	pub fn find_uncle_headers(&self, _parent: &H256) -> Vec<Header> {
+		// TODO
+		Vec::new()
+	}
+
 	/// Get inserted block info which is critical to preapre extras updates.
 	fn block_info(&self, block_bytes: &[u8]) -> BlockInfo {
 		let block = BlockView::new(block_bytes);
diff --git a/ethcore/src/client.rs b/ethcore/src/client.rs
index e5d9f8fcf..4b109c8a3 100644
--- a/ethcore/src/client.rs
+++ b/ethcore/src/client.rs
@@ -418,7 +418,7 @@ impl Client {
 		}
 	}
 
-	/// Set the author that we will seal blocks as.
+	/// Get the author that we will seal blocks as.
 	pub fn author(&self) -> Address {
 		self.author.read().unwrap().clone()
 	}
@@ -428,7 +428,7 @@ impl Client {
 		*self.author.write().unwrap() = author;
 	}
 
-	/// Set the extra_data that we will seal blocks wuth.
+	/// Get the extra_data that we will seal blocks wuth.
 	pub fn extra_data(&self) -> Bytes {
 		self.extra_data.read().unwrap().clone()
 	}
@@ -441,16 +441,19 @@ impl Client {
 	/// New chain head event. Restart mining operation.
 	pub fn prepare_sealing(&self) {
 		let h = self.chain.read().unwrap().best_block_hash();
-		let b = OpenBlock::new(
+		let mut 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),
+			self.build_last_hashes(h.clone()),
 			self.author(),
 			self.extra_data()
 		);
-		// TODO: push uncles.
+
+		self.chain.read().unwrap().find_uncle_headers(&h).into_iter().foreach(|h| { b.push_uncle(h).unwrap(); });
+
 		// TODO: push transactions.
+
 		let b = b.close();
 		trace!("Sealing: number={}, hash={}, diff={}", b.hash(), b.block().header().difficulty(), b.block().header().number());
 		*self.sealing_block.lock().unwrap() = Some(b);
diff --git a/util/src/misc.rs b/util/src/misc.rs
index d9f52fd71..6cd506d02 100644
--- a/util/src/misc.rs
+++ b/util/src/misc.rs
@@ -82,7 +82,7 @@ pub fn version_data() -> Bytes {
 		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.append(&format!("{}", rustc_version::version()));
+	s.append(&&Target::os()[0..2]);
 	s.out()
 }
\ No newline at end of file