diff --git a/src/blockdata/block.rs b/src/blockdata/block.rs
index 3a7f0a0..bcde959 100644
--- a/src/blockdata/block.rs
+++ b/src/blockdata/block.rs
@@ -101,7 +101,7 @@ impl BlockHeader {
     if target != required_target {
       return Err(SpvBadTarget);
     }
-    let ref hash = self.bitcoin_hash().into_uint256();
+    let ref hash = self.bitcoin_hash().into_le();
     if hash <= target { Ok(()) } else { Err(SpvBadProofOfWork) }
   }
 
diff --git a/src/blockdata/blockchain.rs b/src/blockdata/blockchain.rs
index 91df7c9..c73ef6f 100644
--- a/src/blockdata/blockchain.rs
+++ b/src/blockdata/blockchain.rs
@@ -141,20 +141,20 @@ impl<D:SimpleDecoder<E>, E> ConsensusDecodable<D, E> for Blockchain {
     let genesis_hash: Sha256dHash = try!(ConsensusDecodable::consensus_decode(d));
 
     // Lookup best tip
-    let best = match tree.lookup(&best_hash.into_uint256(), 256) {
+    let best = match tree.lookup(&best_hash.into_le(), 256) {
       Some(node) => &**node as NodePtr,
       None => {
         return Err(d.error(format!("best tip {:x} not in tree", best_hash).as_slice()));
       }
     };
     // Lookup genesis
-    if tree.lookup(&genesis_hash.into_uint256(), 256).is_none() {
+    if tree.lookup(&genesis_hash.into_le(), 256).is_none() {
       return Err(d.error(format!("genesis {:x} not in tree", genesis_hash).as_slice()));
     }
     // Reconnect all prev pointers
     let raw_tree = &tree as *const _;
     for node in tree.mut_iter() {
-      let hash = node.block.header.prev_blockhash.into_uint256();
+      let hash = node.block.header.prev_blockhash.into_le();
       let prevptr =
         match unsafe { (*raw_tree).lookup(&hash, 256) } {
           Some(node) => &**node as NodePtr,
@@ -355,7 +355,7 @@ impl Blockchain {
       network: network,
       tree: {
         let mut pat = PatriciaTree::new();
-        pat.insert(&genhash.into_uint256(), 256, new_node);
+        pat.insert(&genhash.into_le(), 256, new_node);
         pat
       },
       best_hash: genhash,
@@ -400,17 +400,17 @@ impl Blockchain {
 
   /// Looks up a block in the chain and returns the BlockchainNode containing it
   pub fn get_block<'a>(&'a self, hash: Sha256dHash) -> Option<&'a BlockchainNode> {
-    self.tree.lookup(&hash.into_uint256(), 256).map(|node| &**node)
+    self.tree.lookup(&hash.into_le(), 256).map(|node| &**node)
   }
 
   /// Locates a block in the chain and overwrites its txdata
   pub fn add_txdata(&mut self, block: Block) -> BitcoinResult<()> {
-    self.replace_txdata(&block.header.bitcoin_hash().into_uint256(), block.txdata, true)
+    self.replace_txdata(&block.header.bitcoin_hash().into_le(), block.txdata, true)
   }
 
   /// Locates a block in the chain and removes its txdata
   pub fn remove_txdata(&mut self, hash: Sha256dHash) -> BitcoinResult<()> {
-    self.replace_txdata(&hash.into_uint256(), vec![], false)
+    self.replace_txdata(&hash.into_le(), vec![], false)
   }
 
   /// Adds a block header to the chain
@@ -430,13 +430,13 @@ impl Blockchain {
       if hash == chain.best_hash { 
         Some(chain.best_tip)
       } else {
-        chain.tree.lookup(&hash.into_uint256(), 256).map(|boxptr| &**boxptr as NodePtr)
+        chain.tree.lookup(&hash.into_le(), 256).map(|boxptr| &**boxptr as NodePtr)
       }
     }
     // Check for multiple inserts (bitcoind from c9a09183 to 3c85d2ec doesn't
     // handle locator hashes properly and may return blocks multiple times,
     // and this may also happen in case of a reorg.
-    if self.tree.lookup(&block.header.bitcoin_hash().into_uint256(), 256).is_some() {
+    if self.tree.lookup(&block.header.bitcoin_hash().into_le(), 256).is_some() {
       return Err(DuplicateHash);
     }
     // Construct node, if possible
@@ -515,7 +515,7 @@ impl Blockchain {
 
     // Insert the new block
     let raw_ptr = &*new_block as NodePtr;
-    self.tree.insert(&new_block.block.header.bitcoin_hash().into_uint256(), 256, new_block);
+    self.tree.insert(&new_block.block.header.bitcoin_hash().into_le(), 256, new_block);
     // Replace the best tip if necessary
     if unsafe { (*raw_ptr).total_work > (*self.best_tip).total_work } {
       self.set_best_tip(raw_ptr);
@@ -565,7 +565,7 @@ impl Blockchain {
 
   /// An iterator over all blocks in the chain starting from `start_hash`
   pub fn iter<'a>(&'a self, start_hash: Sha256dHash) -> BlockIter<'a> {
-    let start = match self.tree.lookup(&start_hash.into_uint256(), 256) {
+    let start = match self.tree.lookup(&start_hash.into_le(), 256) {
         Some(boxptr) => &**boxptr as NodePtr,
         None => RawPtr::null()
       };
@@ -577,7 +577,7 @@ impl Blockchain {
 
   /// An iterator over all blocks in reverse order to the genesis, starting with `start_hash`
   pub fn rev_iter<'a>(&'a self, start_hash: Sha256dHash) -> RevBlockIter<'a> {
-    let start = match self.tree.lookup(&start_hash.into_uint256(), 256) {
+    let start = match self.tree.lookup(&start_hash.into_le(), 256) {
         Some(boxptr) => &**boxptr as NodePtr,
         None => RawPtr::null()
       };
@@ -589,7 +589,7 @@ impl Blockchain {
 
   /// An iterator over all blocks -not- in the best chain, in reverse order, starting from `start_hash`
   pub fn rev_stale_iter<'a>(&'a self, start_hash: Sha256dHash) -> RevStaleBlockIter<'a> {
-    let start = match self.tree.lookup(&start_hash.into_uint256(), 256) {
+    let start = match self.tree.lookup(&start_hash.into_le(), 256) {
         Some(boxptr) => {
           // If we are already on the main chain, we have a dead iterator
           if boxptr.is_on_main_chain(self) {
diff --git a/src/blockdata/utxoset.rs b/src/blockdata/utxoset.rs
index fad3a86..6d438a3 100644
--- a/src/blockdata/utxoset.rs
+++ b/src/blockdata/utxoset.rs
@@ -112,7 +112,7 @@ impl UtxoSet {
     };
     // Get the old value, if any (this is suprisingly possible, c.f. BIP30
     // and the other comments in this file referring to it)
-    let ret = self.table.swap(txid.into_uint128(), new_node);
+    let ret = self.table.swap(txid.into_le().low_128(), new_node);
     if ret.is_none() {
       self.n_utxos += tx.output.len() as u64;
     }
@@ -124,7 +124,7 @@ impl UtxoSet {
     // This whole function has awkward scoping thx to lexical borrow scoping :(
     let (ret, should_delete) = {
       // Locate the UTXO, failing if not found
-      let node = match self.table.find_mut(&txid.into_uint128()) {
+      let node = match self.table.find_mut(&txid.into_le().low_128()) {
         Some(node) => node,
         None => return None
       };
@@ -142,7 +142,7 @@ impl UtxoSet {
 
     // Delete the whole node if it is no longer being used
     if should_delete {
-      self.table.remove(&txid.into_uint128());
+      self.table.remove(&txid.into_le().low_128());
     }
 
     self.n_utxos -= if ret.is_some() { 1 } else { 0 };
@@ -152,7 +152,7 @@ impl UtxoSet {
   /// Get a reference to a UTXO in the set
   pub fn get_utxo<'a>(&'a self, txid: Sha256dHash, vout: u32) -> Option<&'a TxOut> {
     // Locate the UTXO, failing if not found
-    let node = match self.table.find(&txid.into_uint128()) {
+    let node = match self.table.find(&txid.into_le().low_128()) {
       Some(node) => node,
       None => return None
     };
@@ -317,7 +317,7 @@ impl UtxoSet {
         for ((txid, n), txo) in extract_vec.move_iter() {
           // Remove the tx's utxo list and patch the txo into place
           let new_node =
-              match self.table.pop(&txid.into_uint128()) {
+              match self.table.pop(&txid.into_le().low_128()) {
                 Some(mut thinvec) => {
                   let old_len = thinvec.len() as u32;
                   if old_len < n + 1 {
@@ -343,7 +343,7 @@ impl UtxoSet {
                 }
               };
           // Ram it back into the tree
-          self.table.insert(txid.into_uint128(), new_node);
+          self.table.insert(txid.into_le().low_128(), new_node);
         }
       }
       skipped_genesis = true;
diff --git a/src/util/hash.rs b/src/util/hash.rs
index 4b26753..9b356fe 100644
--- a/src/util/hash.rs
+++ b/src/util/hash.rs
@@ -145,20 +145,21 @@ impl Sha256dHash {
 
   /// Converts a hash to a little-endian Uint256
   #[inline]
-  pub fn into_uint256(self) -> Uint256 {
+  pub fn into_le(self) -> Uint256 {
     let Sha256dHash(data) = self;
-    unsafe { Uint256(transmute(data)) }
+    let mut ret: [u64, ..4] = unsafe { transmute(data) };
+    for x in ret.as_mut_slice().mut_iter() { *x = x.to_le(); }
+    Uint256(ret)
   }
 
-  /// Converts a hash to a little-endian Uint128, using only the "low" bytes
+  /// Converts a hash to a big-endian Uint256
   #[inline]
-  pub fn into_uint128(self) -> Uint128 {
-    let Sha256dHash(data) = self;
-    // TODO: this function won't work correctly on big-endian machines
-    unsafe { Uint128(transmute([data[16], data[17], data[18], data[19], data[20],
-                                data[21], data[22], data[23], data[24], data[25],
-                                data[26], data[27], data[28], data[29], data[30],
-                                data[31]])) }
+  pub fn into_be(self) -> Uint256 {
+    let Sha256dHash(mut data) = self;
+    data.reverse();
+    let mut ret: [u64, ..4] = unsafe { transmute(data) };
+    for x in ret.mut_iter() { *x = x.to_be(); }
+    Uint256(ret)
   }
 
   /// Converts a hash to a Hash32 by truncation
@@ -384,5 +385,15 @@ mod tests {
                "\"56944c5d3f98413ef45cf54545538103cc9f298e0575820ad3591376e2e0f65d\"".as_bytes());
     assert_eq!(json::decode(from_utf8(res.as_slice()).unwrap()), Ok(hash));
   }
+
+  #[test]
+  fn test_sighash_single_vec() {
+    let one = Sha256dHash([1, 0, 0, 0, 0, 0, 0, 0,
+                           0, 0, 0, 0, 0, 0, 0, 0,
+                           0, 0, 0, 0, 0, 0, 0, 0,
+                           0, 0, 0, 0, 0, 0, 0, 0]);
+    assert_eq!(Some(one.into_le()), FromPrimitive::from_u64(1));
+    assert_eq!(Some(one.into_le().low_128()), FromPrimitive::from_u64(1));
+  }
 }
 
diff --git a/src/util/patricia_tree.rs b/src/util/patricia_tree.rs
index c06edc8..95e2bae 100644
--- a/src/util/patricia_tree.rs
+++ b/src/util/patricia_tree.rs
@@ -553,7 +553,7 @@ mod tests {
     let mut tree = PatriciaTree::new();
     let mut hashes = vec![];
     for i in range(0u32, 5000) {
-      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_uint128();
+      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_le().low_128();
       tree.insert(&hash, 250, i);
       hashes.push(hash);
     }
@@ -594,7 +594,7 @@ mod tests {
     let mut hashes = vec![];
     // Start by inserting a bunch of chunder
     for i in range(1u32, 500) {
-      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_uint128();
+      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_le().low_128();
       tree.insert(&hash, 128, i * 1000);
       hashes.push(hash);
     }
@@ -626,7 +626,7 @@ mod tests {
     let mut data = Vec::from_elem(n_elems, None);
     // Start by inserting a bunch of stuff
     for i in range(0, n_elems) {
-      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_uint128();
+      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_le().low_128();
       tree.insert(&hash, 128, i);
       *data.get_mut(i) = Some(());
     }
@@ -648,7 +648,7 @@ mod tests {
     let mut data = Vec::from_elem(n_elems, None);
     // Start by inserting a bunch of stuff
     for i in range(0, n_elems) {
-      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_uint128();
+      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_le().low_128();
       tree.insert(&hash, 128, i);
       *data.get_mut(i) = Some(());
     }
@@ -674,7 +674,7 @@ mod tests {
     let mut tree = PatriciaTree::new();
     let mut hashes = vec![];
     for i in range(0u32, 5000) {
-      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_uint128();
+      let hash = Sha256dHash::from_data(&[(i / 0x100) as u8, (i % 0x100) as u8]).into_le().low_128();
       tree.insert(&hash, 250, i);
       hashes.push(hash);
     }
diff --git a/src/util/uint.rs b/src/util/uint.rs
index 3946f36..e7b47ef 100644
--- a/src/util/uint.rs
+++ b/src/util/uint.rs
@@ -367,6 +367,13 @@ impl Uint256 {
       }
     }
   }
+
+  /// Decay to a uint128
+  #[inline]
+  pub fn low_128(&self) -> Uint128 {
+    let &Uint256(data) = self;
+    Uint128([data[0], data[1]])
+  }
 }
 
 #[cfg(test)]