diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index 932936fe..74f6fd54 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -174,7 +174,7 @@ Mempool.prototype.getRangeSync = function getRangeSync(options) {
   var i, tx;
 
   for (i = 0; i < hashes.length; i++) {
-    tx = this.getTXSync(hashes[i].toString('hex'));
+    tx = this.getTXSync(hashes[i]);
     if (tx)
       txs.push(tx);
   }
@@ -230,7 +230,7 @@ Mempool.prototype.getCoinSync = function getCoinSync(hash, index) {
 Mempool.prototype.isSpentSync = function isSpentSync(hash, index) {
   var key = hash + '/' + index;
 
-  return this.spent[key];
+  return this.spent[key] != null;
 };
 
 Mempool.prototype.isDoubleSpendSync = function isDoubleSpendSync(tx) {
@@ -303,7 +303,7 @@ Mempool.prototype.getTXByAddressSync = function getTXByAddressSync(addresses, ca
 };
 
 Mempool.prototype.fillTXSync = function fillTXSync(tx) {
-  var i, input, tx;
+  var i, input, prev;
 
   if (tx.isCoinbase())
     return tx;
@@ -314,12 +314,12 @@ Mempool.prototype.fillTXSync = function fillTXSync(tx) {
     if (input.coin)
       continue;
 
-    tx = this.getTXSync(input.prevout.hash);
+    prev = this.getTXSync(input.prevout.hash);
 
-    if (!tx)
+    if (!prev)
       continue;
 
-    input.coin = bcoin.coin(tx, input.prevout.index);
+    input.coin = bcoin.coin(prev, input.prevout.index);
   }
 
   return tx;
@@ -468,6 +468,7 @@ Mempool.prototype.addTX = function addTX(tx, callback, force) {
 
 // Use bitcoinj-style confidence calculation
 Mempool.prototype.getConfidence = function getConfidence(hash, callback) {
+  var self = this;
   var tx;
 
   callback = utils.asyncify(callback);
@@ -489,14 +490,28 @@ Mempool.prototype.getConfidence = function getConfidence(hash, callback) {
   if (this.hasTXSync(hash))
     return callback(null, constants.confidence.PENDING);
 
-  this.chain.db.getTX(hash, function(err, existing) {
+  function getBlock(callback) {
+    if (tx && tx.block)
+      return callback(null, tx.block);
+    return self.chain.db.getTX(hash, function(err, existing) {
+      if (err)
+        return callback(err);
+
+      if (!existing)
+        return callback();
+
+      return callback(null, existing.block);
+    });
+  }
+
+  return getBlock(function(err, block) {
     if (err)
       return callback(err);
 
-    if (!existing)
+    if (!block)
       return callback(null, constants.confidence.UNKNOWN);
 
-    self.chain.db.isMainChain(existing.block, function(err, result) {
+    self.chain.db.isMainChain(block, function(err, result) {
       if (err)
         return callback(err);
 
@@ -590,7 +605,7 @@ Mempool.prototype.addUnchecked = function addUnchecked(tx, callback) {
 
 Mempool.prototype.removeUnchecked = function removeUnchecked(tx, callback) {
   var self = this;
-  var hash, input, output, i, key, coin;
+  var hash, input, output, i, key, coin, prev;
 
   callback = utils.asyncify(callback);
 
@@ -622,6 +637,16 @@ Mempool.prototype.removeUnchecked = function removeUnchecked(tx, callback) {
     delete this.coins[key];
     delete this.spent[key];
     this.addressMap.removeCoin(input);
+    try {
+      prev = this.getTXSync(input.prevout.hash);
+    } catch (e) {
+      return callback(e);
+    }
+    if (prev) {
+      coin = bcoin.coin(prev, input.prevout.index);
+      this.coins[key] = coin.toRaw();
+      this.addressMap.addCoin(coin);
+    }
   }
 
   for (i = 0; i < tx.outputs.length; i++) {
@@ -832,7 +857,7 @@ Mempool.prototype.getOrphanSync = function getOrphanSync(hash) {
   orphan = this.orphans[hash];
 
   if (!orphan)
-    return callback();
+    return;
 
   return bcoin.tx.fromExtended(orphan, true);
 };
@@ -1364,7 +1389,6 @@ function BinaryIndex() {
 }
 
 BinaryIndex.prototype.insert = function insert(tx) {
-  var hash = tx.hash();
   var ps = new Buffer(4);
   var index;
 
@@ -1373,12 +1397,11 @@ BinaryIndex.prototype.insert = function insert(tx) {
   index = binarySearch(this.index, ps, true);
 
   this.index.splice(index + 1, 0, ps);
-  this.data.splice(index + 1, 0, hash);
+  this.data.splice(index + 1, 0, tx.hash());
 };
 
 BinaryIndex.prototype.remove = function remove(tx) {
-  var hash = tx.hash();
-  var index = binarySearch(this.data, hash);
+  var index = binarySearch(this.data, tx.hash());
 
   if (index !== -1) {
     this.index.splice(index, 1);
@@ -1399,7 +1422,7 @@ BinaryIndex.prototype.range = function range(start, end) {
     ps = utils.readU32BE(this.index[i], 0);
     if (ps < start || ps > end)
       return hashes;
-    hashes.push(this.data[i]);
+    hashes.push(this.data[i].toString('hex'));
   }
 
   return hashes;
@@ -1430,9 +1453,6 @@ function binarySearch(items, key, insert) {
   if (!insert)
     return -1;
 
-  if (start === 0)
-    return -1;
-
   return start - 1;
 }