diff --git a/lib/bcoin/blockdb.js b/lib/bcoin/blockdb.js
index dbb291e0..38422c85 100644
--- a/lib/bcoin/blockdb.js
+++ b/lib/bcoin/blockdb.js
@@ -1242,6 +1242,15 @@ BlockData.prototype.truncateAsync = function truncateAsync(size, callback) {
   });
 };
 
+BlockData.prototype._ioError = function _ioError(name, size, offset) {
+  return new Error(name
+    + '() failed at offset '
+    + offset
+    + ' with '
+    + size
+    + ' bytes left.');
+};
+
 BlockData.prototype._readSync = function _readSync(size, offset) {
   var index = 0;
   var data, bytes;
@@ -1271,7 +1280,7 @@ BlockData.prototype._readSync = function _readSync(size, offset) {
 
   this._free(data);
 
-  throw new Error('_readSync() failed.');
+  throw this._ioError('_readSync', size, offset);
 };
 
 BlockData.prototype._readAsync = function _readAsync(size, offset, callback) {
@@ -1297,7 +1306,7 @@ BlockData.prototype._readAsync = function _readAsync(size, offset, callback) {
       }
 
       if (!bytes)
-        return callback(new Error('_readAsync() failed at offset ' + offset + ' ' + size + ' to go'));
+        return callback(self._ioError('_readAsync', size, offset));
 
       index += bytes;
       size -= bytes;
@@ -1342,7 +1351,9 @@ BlockData.prototype._writeSync = function _writeSync(data, offset) {
     throw e;
   }
 
-  throw new Error('_writeSync() failed.');
+  fs.fsyncSync(this.fd);
+
+  throw this._ioError('_writeSync', size, offset);
 };
 
 BlockData.prototype._writeAsync = function _writeAsync(data, offset, callback) {
@@ -1372,7 +1383,7 @@ BlockData.prototype._writeAsync = function _writeAsync(data, offset, callback) {
       }
 
       if (!bytes)
-        return callback(new Error('_writeAsync() failed.'));
+        return callback(self._ioError('_writeAsync', size, offset));
 
       index += bytes;
       size -= bytes;
diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 935c2856..35309311 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -47,6 +47,8 @@ function Chain(options) {
   this.pendingLimit = options.pendingLimit || 10 * 1024 * 1024;
   this.invalid = {};
   this.bestHeight = -1;
+  this.lastUpdate = utils.now();
+  this.blockDelta = 0;
 
   this.orphan = {
     map: {},
@@ -716,7 +718,7 @@ Chain.prototype._fillBlock = function _fillBlock(block, callback) {
 
 Chain.prototype._addEntry = function _addEntry(entry, block, callback) {
   var self = this;
-  var existing;
+  var existing, now;
 
   callback = utils.asyncify(callback);
 
@@ -731,6 +733,10 @@ Chain.prototype._addEntry = function _addEntry(entry, block, callback) {
   if (existing && existing.hash === entry.hash)
     return callback(null, false);
 
+  now = utils.now();
+  this.blockDelta = now - this.lastUpdate;
+  this.lastUpdate = now;
+
   this._saveBlock(block, function(err) {
     if (err)
       return callback(err);
@@ -1539,6 +1545,14 @@ Chain.prototype.isFull = function isFull() {
   return delta < 40 * 60;
 };
 
+Chain.prototype.isInitial = function isInitial() {
+  if (!this.tip)
+    return true;
+
+  // Should mimic the original IsInitialBlockDownload() function
+  return this.blockDelta < 10 && this.tip.ts < utils.now() - 24 * 60 * 60;
+};
+
 Chain.prototype.getProgress = function getProgress() {
   if (!this.tip)
     return 0;
diff --git a/lib/bcoin/chaindb.js b/lib/bcoin/chaindb.js
index b3bcf89e..b93034f8 100644
--- a/lib/bcoin/chaindb.js
+++ b/lib/bcoin/chaindb.js
@@ -47,6 +47,7 @@ function ChainDB(chain, options) {
   this.size = 0;
   this.fd = null;
   this.loading = false;
+  this.loaded = false;
 
   // Need to cache up to the retarget interval
   // if we're going to be checking the damn
@@ -122,6 +123,7 @@ ChainDB.prototype.load = function load(start, callback) {
 
   function finish(err) {
     self.loading = false;
+    self.loaded = true;
     self.emit('load');
 
     if (err)
@@ -617,6 +619,15 @@ ChainDB.prototype.has = function has(height) {
   return false;
 };
 
+ChainDB.prototype._ioError = function _ioError(name, size, offset) {
+  return new Error(name
+    + '() failed at offset '
+    + offset
+    + ' with '
+    + size
+    + ' bytes left.');
+};
+
 ChainDB.prototype._readSync = function _readSync(size, offset) {
   var index = 0;
   var data, bytes;
@@ -646,7 +657,7 @@ ChainDB.prototype._readSync = function _readSync(size, offset) {
 
   this._free(data);
 
-  throw new Error('_readSync() failed.');
+  throw this._ioError('_readSync', size, offset);
 };
 
 ChainDB.prototype._readAsync = function _readAsync(size, offset, callback) {
@@ -672,7 +683,7 @@ ChainDB.prototype._readAsync = function _readAsync(size, offset, callback) {
       }
 
       if (!bytes)
-        return callback(new Error('_readAsync() failed.'));
+        return callback(self._ioError('_readAsync', size, offset));
 
       index += bytes;
       size -= bytes;
@@ -717,7 +728,9 @@ ChainDB.prototype._writeSync = function _writeSync(data, offset) {
     throw e;
   }
 
-  throw new Error('_writeSync() failed.');
+  fs.fsyncSync(this.fd);
+
+  throw this._ioError('_writeSync', size, offset);
 };
 
 ChainDB.prototype._writeAsync = function _writeAsync(data, offset, callback) {
@@ -747,14 +760,23 @@ ChainDB.prototype._writeAsync = function _writeAsync(data, offset, callback) {
       }
 
       if (!bytes)
-        return callback(new Error('_writeAsync() failed.'));
+        return callback(self._ioError('_writeAsync', size, offset));
 
       index += bytes;
       size -= bytes;
       offset += bytes;
 
-      if (index === data.length)
-        return callback(null, true);
+      if (index === data.length) {
+        // Don't fsync when we're
+        // potentially preloading headers.
+        if (!self.chain.loaded)
+          return callback(null, true);
+        return fs.fsync(self.fd, function(err) {
+          if (err)
+            return callback(err);
+          return callback(null, true);
+        });
+      }
 
       next();
     });