diff --git a/utils/package.json b/utils/package.json
index 8b18bd1c6..5615992bf 100644
--- a/utils/package.json
+++ b/utils/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ethers-utils",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "description": "Utilities for the Ethers Ethereum library.",
   "bugs": {
     "url": "http://github.com/ethers-io/ethers.js/issues",
diff --git a/utils/pbkdf2.js b/utils/pbkdf2.js
index 6196a8cca..21ddc5882 100644
--- a/utils/pbkdf2.js
+++ b/utils/pbkdf2.js
@@ -1,3 +1,6 @@
+'use strict';
+
+var convert = require('./convert');
 
 function pbkdf2(password, salt, iterations, keylen, createHmac) {
     var hLen
@@ -39,31 +42,10 @@ function pbkdf2(password, salt, iterations, keylen, createHmac) {
         var destPos = (i - 1) * hLen
         var len = (i === l ? r : hLen)
         //T.copy(DK, destPos, 0, len)
-        DK.set(Array.prototype.slice.call(T, 0, len), destPos);
-
+        DK.set(convert.arrayify(T).slice(0, len), destPos);
     }
 
-    return DK
+    return convert.arrayify(DK)
 }
 
-/*
-var hmac = require('./hmac.js');
-var utf8 = require('./utf8.js');
-var p = require('pbkdf2');
-
-var pw = utf8.toUtf8Bytes('password');
-var sa = utf8.toUtf8Bytes('salt');
-
-var t0 = (new Date()).getTime();
-for (var i = 0; i < 100; i++) {
-    pbkdf2(pw, sa, 1000, 40, hmac.createSha512Hmac);
-}
-var t1 = (new Date()).getTime();
-for (var i = 0; i < 100; i++) {
-    p.pbkdf2Sync('password', 'salt', 1000, 40, 'sha512');
-}
-var t2 = (new Date()).getTime();
-
-console.log('TT', t1 - t0, t2 - t1);
-*/
 module.exports = pbkdf2;
diff --git a/wallet/hdnode.js b/wallet/hdnode.js
index f4d50da25..5d4fa93de 100644
--- a/wallet/hdnode.js
+++ b/wallet/hdnode.js
@@ -82,7 +82,7 @@ utils.defineProperty(HDNode.prototype, '_derive', function(index) {
     // Data += ser_32(i)
     for (var i = 24; i >= 0; i -= 8) { data[33 + (i >> 3)] = ((index >> (24 - i)) & 0xff); }
 
-    var I = utils.createSha512Hmac(this.chainCode).update(data).digest();
+    var I = utils.arrayify(utils.createSha512Hmac(this.chainCode).update(data).digest());
     var IL = utils.bigNumberify(I.slice(0, 32));
     var IR = I.slice(32);
 
@@ -130,7 +130,7 @@ utils.defineProperty(HDNode, 'fromSeed', function(seed) {
     seed = utils.arrayify(seed);
     if (seed.length < 16 || seed.length > 64) { throw new Error('invalid seed'); }
 
-    var I = utils.createSha512Hmac(MasterSecret).update(seed).digest();
+    var I = utils.arrayify(utils.createSha512Hmac(MasterSecret).update(seed).digest());
 
     return new HDNode(secp256k1.keyFromPrivate(I.slice(0, 32)), I.slice(32), 0, 0, 0);
 });
@@ -160,7 +160,7 @@ function mnemonicToEntropy(mnemonic) {
    var words = mnemonic.toLowerCase().split(' ');
    if ((words.length % 3) !== 0) { throw new Error('invalid mnemonic'); }
 
-   var entropy = new Uint8Array(Math.ceil(11 * words.length / 8));
+   var entropy = utils.arrayify(new Uint8Array(Math.ceil(11 * words.length / 8)));
 
    var offset = 0;
    for (var i = 0; i < words.length; i++) {
diff --git a/wallet/package.json b/wallet/package.json
index ae6cfa88d..0039f38c4 100644
--- a/wallet/package.json
+++ b/wallet/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ethers-wallet",
-  "version": "2.1.3",
+  "version": "2.1.4",
   "description": "Wallet and signing library for Ethereum.",
   "bugs": {
     "url": "http://github.com/ethers-io/ethers.js/issues",