diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 1281c958..867a4f9b 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -917,6 +917,8 @@ ChainDB.prototype.saveAsync = function saveAsync(entry, callback) {
   var self = this;
   var raw, offset;
 
+  callback = utils.asyncify(callback);
+
   // Cache the past 1001 blocks in memory
   // (necessary for isSuperMajority)
   this.cache(entry);
@@ -926,7 +928,7 @@ ChainDB.prototype.saveAsync = function saveAsync(entry, callback) {
   // it cancels.
   if (this._queue[entry.height]) {
     this._queue[entry.height] = entry;
-    return;
+    return callback();
   }
 
   // Speed up writes by doing them asynchronously
@@ -957,14 +959,15 @@ ChainDB.prototype.saveAsync = function saveAsync(entry, callback) {
 
     delete self._queue[entry.height];
 
-    if (callback)
-      return callback(null, success);
+    return callback(null, success);
   });
 };
 
 ChainDB.prototype.remove = function remove(height) {
   assert(height >= 0);
 
+  // Potential race condition here. Not sure how
+  // to handle this.
   if (this._queue[height]) {
     utils.debug('Warning: write job in progress.');
     delete this._queue[height];
@@ -1005,6 +1008,12 @@ ChainDB.prototype.has = function has(height) {
   if (this._queue[height] || this._cache[height])
     return true;
 
+  if (height < 0 || height == null)
+    return false;
+
+  if ((height + 1) * BLOCK_SIZE > this.size)
+    return false;
+
   data = this._readSync(4, height * BLOCK_SIZE);
 
   if (!data)
@@ -1033,6 +1042,7 @@ ChainDB.prototype._readSync = function _readSync(size, offset) {
       }
     }
   } catch (e) {
+    this._free(data);
     throw e;
   }
 
@@ -1041,7 +1051,7 @@ ChainDB.prototype._readSync = function _readSync(size, offset) {
   throw new Error('_readSync() failed.');
 };
 
-ChainDB.prototype._readAsync = function _readSync(size, offset, callback) {
+ChainDB.prototype._readAsync = function _readAsync(size, offset, callback) {
   var self = this;
   var index = 0;
   var data, bytes;