diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 9566e5ac..a2969592 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -1038,7 +1038,7 @@ Chain.prototype._syncHeight = function _syncHeight(callback, force) {
   if (!unlock)
     return;
 
-  callback = utils.asyncify(callback);
+  callback = utils.ensure(callback);
 
   function done(err, result) {
     unlock();
@@ -1052,10 +1052,10 @@ Chain.prototype._syncHeight = function _syncHeight(callback, force) {
     if (chainHeight == null || chainHeight < 0)
       return done(new Error('Bad chain height.'));
 
-    if (!this.blockdb)
+    if (!self.blockdb)
       return done();
 
-    this.blockdb.getHeight(function(err, blockHeight) {
+    self.blockdb.getHeight(function(err, blockHeight) {
       if (err)
         return done(err);