diff --git a/lib/bcoin/coin.js b/lib/bcoin/coin.js
index d51a66fb..abb15466 100644
--- a/lib/bcoin/coin.js
+++ b/lib/bcoin/coin.js
@@ -176,6 +176,28 @@ Coin.fromRaw = function fromRaw(data, enc) {
   return new Coin(Coin._fromRaw(data, enc));
 };
 
+Coin.prototype.toUTXO = function toUTXO(enc) {
+  var data = bcoin.protocol.framer.utxo(this);
+
+  if (enc === 'hex')
+    data = utils.toHex(data);
+
+  return data;
+};
+
+Coin._fromUTXO = function _fromUTXO(data, enc) {
+  if (enc === 'hex')
+    data = new Buffer(data, 'hex');
+
+  data = bcoin.protocol.parser.parseUTXO(data);
+
+  return data;
+};
+
+Coin.fromUTXO = function fromUTXO(data, enc) {
+  return new Coin(Coin._fromUTXO(data, enc));
+};
+
 Coin.prototype.toExtended = function toExtended(enc) {
   var data = bcoin.protocol.framer.coin(this, true);
 
diff --git a/lib/bcoin/ldb.js b/lib/bcoin/ldb.js
index 3b2c5a3c..1ed24877 100644
--- a/lib/bcoin/ldb.js
+++ b/lib/bcoin/ldb.js
@@ -17,30 +17,27 @@ module.exports = function ldb(name, options) {
     : process.env.BCOIN_DB;
 
   if (!db[file]) {
-    if (options.db && typeof options.db !== 'string') {
-      bcoin.ensurePrefix();
-      backend = options.db;
-    } else if (bcoin.isBrowser && backend !== 'memdown') {
+    if (!options)
+      options = {};
+
+    if (!backend || backend === 'leveldb')
+      backend = 'leveldown';
+    else if (backend === 'rocksdb')
+      backend = 'rocksdown';
+    else if (backend === 'lmdb')
+      backend = 'lmdb';
+    else if (backend === 'memory')
+      backend = 'memdown';
+
+    if (bcoin.isBrowser && backend !== 'memdown') {
       backend = require('level-js');
     } else {
-      if (!backend || backend === 'leveldb')
-        backend = 'leveldown';
-      else if (backend === 'rocksdb')
-        backend = 'rocksdown';
-      else if (backend === 'lmdb')
-        backend = 'lmdb';
-      else if (backend === 'memory')
-        backend = 'memdown';
-
       if (backend !== 'memdown')
         bcoin.ensurePrefix();
 
       backend = require(backend);
     }
 
-    if (!options)
-      options = {};
-
     db[file] = new LowlevelUp(file, {
       keyEncoding: 'ascii',
       valueEncoding: 'binary',
@@ -100,12 +97,9 @@ function LowlevelUp(file, options) {
     this.db = this.db.db;
 
   this.binding = this.db;
-  this.hasBinding = false;
 
-  if (this.db.binding) {
+  if (this.db.binding)
     this.binding = this.db.binding;
-    this.hasBinding = true;
-  }
 
   this.binding.open(options, function(err) {
     if (err)
@@ -161,8 +155,6 @@ LowlevelUp.prototype.batch = function batch(ops, options, callback) {
 };
 
 LowlevelUp.prototype.iterator = function iterator(options) {
-  if (this.hasBinding)
-    return new Iterator(this.binding, options);
   return this.db.iterator(options);
 };
 
@@ -176,55 +168,3 @@ LowlevelUp.prototype.getProperty = function getProperty(name) {
 LowlevelUp.prototype.approximateSize = function approximateSize(start, end, callback) {
   return this.binding.approximateSize(start, end, callback);
 };
-
-function Iterator(binding, options) {
-  this.binding = binding.iterator(options);
-  this.cache = null;
-  this.finished = false;
-}
-
-Iterator.prototype.seek = function (key) {
-  if (typeof key !== 'string')
-    throw new Error('seek requires a string key');
-  if (this.cache)
-    this.cache.length = 0;
-  this.cache = null;
-  this.binding.seek(key);
-};
-
-Iterator.prototype.next = function next(callback) {
-  var self = this;
-  var key, value;
-
-  if (this.cache && this.cache.length) {
-    key = this.cache.pop();
-    value = this.cache.pop();
-
-    utils.nextTick(function() {
-      callback(null, key, value);
-    });
-  } else if (this.finished) {
-    utils.nextTick(function() {
-      callback();
-    });
-  } else {
-    this.binding.next(function(err, array, finished) {
-      if (err)
-        return callback(err);
-
-      self.cache = array;
-      self.finished = finished;
-      self.next(callback);
-    });
-  }
-
-  return this;
-};
-
-Iterator.prototype.end = function end(callback) {
-  if (this.cache)
-    this.cache.length = 0;
-  delete this.cache;
-  this.binding.end(callback);
-  delete this.binding;
-};
diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index 9227bf48..14977c5e 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -100,7 +100,7 @@ Mempool.prototype.open = function open(callback) {
   return this.db.open(callback);
 };
 
-Mempool.prototype.addBlock = function addBlock(block) {
+Mempool.prototype.addBlock = function addBlock(block, callback) {
   var self = this;
   callback = utils.ensure(callback);
   // Remove now-mined transactions
@@ -139,7 +139,7 @@ Mempool.prototype.getCoinsByAddress = function getCoinsByAddress(addresses, call
 };
 
 Mempool.prototype.getByAddress =
-Mempool.prototype.getTXByAddress = function getTXByAddress(addresses) {
+Mempool.prototype.getTXByAddress = function getTXByAddress(addresses, callback) {
   return this.tx.getTXByAddress(addresses, callback);
 };
 
@@ -253,9 +253,8 @@ Mempool.prototype.addUnchecked = function addUnchecked(tx, peer, callback) {
 
       utils.forEachSerial(resolved, function(tx, next) {
         self.addUnchecked(tx, peer, function(err) {
-          if (err) {
+          if (err)
             self.emit('error', err);
-          }
           next();
         }, true);
       }, callback);
diff --git a/lib/bcoin/protocol/framer.js b/lib/bcoin/protocol/framer.js
index 047e5e7f..26dc428c 100644
--- a/lib/bcoin/protocol/framer.js
+++ b/lib/bcoin/protocol/framer.js
@@ -106,8 +106,7 @@ Framer.prototype.getBlocks = function getBlocks(hashes, stop) {
   return this.packet('getblocks', Framer.getBlocks(hashes, stop));
 };
 
-Framer.prototype.utxo =
-Framer.prototype.coin = function _coin(coin) {
+Framer.prototype.utxo = function _coin(coin) {
   return this.packet('utxo', Framer.coin(coin, false));
 };
 
@@ -319,8 +318,7 @@ Framer._getBlocks = function _getBlocks(hashes, stop, writer) {
   return p;
 };
 
-Framer.utxo =
-Framer.coin = function _coin(coin, extended, writer) {
+Framer.utxo = function _utxo(coin, writer) {
   var p = new BufferWriter(writer);
   var height = coin.height;
 
@@ -334,8 +332,28 @@ Framer.coin = function _coin(coin, extended, writer) {
   p.write64(coin.value);
   p.writeVarBytes(coin.script.encode());
 
+  if (!writer)
+    p = p.render();
+
+  return p;
+};
+
+Framer.coin = function _coin(coin, extended, writer) {
+  var p = new BufferWriter(writer);
+  var height = coin.height;
+
+  if (height === -1)
+    height = 0x7fffffff;
+
+  assert(coin.value.byteLength() <= 8);
+
+  p.writeU32(coin.version);
+  p.writeU32(height);
+  p.write64(coin.value);
+  p.writeVarBytes(coin.script.encode());
+  p.writeU8(coin.coinbase ? 1 : 0);
+
   if (extended) {
-    p.writeU8(coin.coinbase ? 1 : 0);
     p.writeHash(coin.hash);
     p.writeU32(coin.index);
   }
diff --git a/lib/bcoin/protocol/parser.js b/lib/bcoin/protocol/parser.js
index 96770f2c..ac2a1c90 100644
--- a/lib/bcoin/protocol/parser.js
+++ b/lib/bcoin/protocol/parser.js
@@ -436,6 +436,29 @@ Parser.parseOutput = function parseOutput(p) {
   };
 };
 
+Parser.parseUTXO = function parseUTXO(p) {
+  var version, height, value, script, hash, index, coinbase;
+
+  p = new BufferReader(p);
+  p.start();
+
+  version = p.readU32();
+  height = p.readU32();
+  value = p.read64();
+  script = new bcoin.script(p.readVarBytes());
+
+  if (height === 0x7fffffff)
+    height = -1;
+
+  return {
+    version: version,
+    height: height,
+    value: value,
+    script: script,
+    _size: p.end()
+  };
+};
+
 Parser.parseCoin = function parseCoin(p, extended) {
   var version, height, value, script, hash, index, coinbase;
 
@@ -444,32 +467,26 @@ Parser.parseCoin = function parseCoin(p, extended) {
 
   version = p.readU32();
   height = p.readU32();
+  value = p.read64();
+  script = new bcoin.script(p.readVarBytes());
+  coinbase = p.readU8() === 1;
+
+  if (extended) {
+    hash = p.readHash();
+    index = p.readU32();
+  }
 
   if (height === 0x7fffffff)
     height = -1;
 
-  value = p.read64();
-
-  script = new bcoin.script(p.readVarBytes());
-
-  if (extended) {
-    coinbase = p.readU8() === 1;
-    hash = p.readHash();
-    index = p.readU32();
-  } else {
-    coinbase = false;
-    hash = utils.slice(constants.zeroHash);
-    index = 0xffffffff;
-  }
-
   return {
     version: version,
     height: height,
     value: value,
     script: script,
+    coinbase: coinbase,
     hash: hash,
     index: index,
-    coinbase: coinbase,
     _size: p.end()
   };
 };
diff --git a/lib/bcoin/txdb.js b/lib/bcoin/txdb.js
index e43371fa..b0d3b6a6 100644
--- a/lib/bcoin/txdb.js
+++ b/lib/bcoin/txdb.js
@@ -327,7 +327,7 @@ TXPool.prototype._add = function add(tx, map, callback, force) {
     utils.forEachSerial(tx.inputs, function(input, next, i) {
       var key;
 
-      if (input.isCoinbase())
+      if (tx.isCoinbase())
         return next();
 
       key = input.prevout.hash + '/' + input.prevout.index;
@@ -344,9 +344,6 @@ TXPool.prototype._add = function add(tx, map, callback, force) {
           // Add TX to inputs and spend money
           input.output = coin;
 
-          assert(input.prevout.hash === coin.hash);
-          assert(input.prevout.index === coin.index);
-
           // Skip invalid transactions
           if (self.options.verify) {
             if (!tx.verify(i))
@@ -487,7 +484,7 @@ TXPool.prototype._add = function add(tx, map, callback, force) {
                 });
               }
 
-              batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toExtended());
+              batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toRaw());
               updated = true;
             }
 
@@ -640,7 +637,7 @@ TXPool.prototype._confirm = function _confirm(tx, map, callback, force) {
 
         coin.height = tx.height;
 
-        batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toExtended());
+        batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toRaw());
 
         next();
       });
@@ -768,7 +765,7 @@ TXPool.prototype._remove = function remove(tx, map, callback, force) {
     tx.inputs.forEach(function(input) {
       var address = input.getAddress();
 
-      if (input.isCoinbase())
+      if (tx.isCoinbase())
         return;
 
       if (!input.output)
@@ -791,7 +788,7 @@ TXPool.prototype._remove = function remove(tx, map, callback, force) {
       batch.put(prefix + 'u/t/'
         + input.prevout.hash
         + '/' + input.prevout.index,
-        input.output.toExtended());
+        input.output.toRaw());
 
       if (self.options.indexSpent) {
         batch.del(prefix + 's/t/'
@@ -920,7 +917,7 @@ TXPool.prototype._unconfirm = function unconfirm(tx, map, callback, force) {
 
       coin.height = tx.height;
 
-      batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toExtended());
+      batch.put(prefix + 'u/t/' + hash + '/' + i, coin.toRaw());
 
       next();
     });
@@ -1494,7 +1491,7 @@ TXPool.prototype.getCoin = function getCoin(hash, index, callback) {
       return callback();
 
     try {
-      coin = bcoin.coin.fromExtended(coin);
+      coin = bcoin.coin.fromRaw(coin);
       coin.hash = hash;
       coin.index = index;
     } catch (e) {