diff --git a/lib/hdprivatekey.js b/lib/hdprivatekey.js
index 0b157c3..69ed415 100644
--- a/lib/hdprivatekey.js
+++ b/lib/hdprivatekey.js
@@ -221,7 +221,7 @@ HDPrivateKey.prototype._buildFromObject = function(arg) {
   // TODO: Type validation
   var buffers = {
     version: arg.network ? BufferUtil.integerAsBuffer(Network.get(arg.network).xprivkey) : arg.version,
-    depth: BufferUtil.integerAsSingleByteBuffer(arg.depth),
+    depth: _.isNumber(arg.depth) ? BufferUtil.integerAsSingleByteBuffer(arg.depth) : arg.depth,
     parentFingerPrint: _.isNumber(arg.parentFingerPrint) ? BufferUtil.integerAsBuffer(arg.parentFingerPrint) : arg.parentFingerPrint,
     childIndex: _.isNumber(arg.childIndex) ? BufferUtil.integerAsBuffer(arg.childIndex) : arg.childIndex,
     chainCode: _.isString(arg.chainCode) ? BufferUtil.hexToBuffer(arg.chainCode) : arg.chainCode,
diff --git a/lib/hdpublickey.js b/lib/hdpublickey.js
index fa00708..8599556 100644
--- a/lib/hdpublickey.js
+++ b/lib/hdpublickey.js
@@ -231,9 +231,9 @@ HDPublicKey.prototype._buildFromObject = function (arg) {
   // TODO: Type validation
   var buffers = {
     version: arg.network ? BufferUtil.integerAsBuffer(Network.get(arg.network).xpubkey) : arg.version,
-    depth: BufferUtil.integerAsSingleByteBuffer(arg.depth),
+    depth: _.isNumber(arg.depth) ? BufferUtil.integerAsSingleByteBuffer(arg.depth) : arg.depth,
     parentFingerPrint: _.isNumber(arg.parentFingerPrint) ? BufferUtil.integerAsBuffer(arg.parentFingerPrint) : arg.parentFingerPrint,
-    childIndex: BufferUtil.integerAsBuffer(arg.childIndex),
+    childIndex: _.isNumber(arg.childIndex) ? BufferUtil.integerAsBuffer(arg.childIndex) : arg.childIndex,
     chainCode: _.isString(arg.chainCode) ? BufferUtil.hexToBuffer(arg.chainCode) : arg.chainCode,
     publicKey: _.isString(arg.publicKey) ? BufferUtil.hexToBuffer(arg.publicKey) :
       BufferUtil.isBuffer(arg.publicKey) ? arg.publicKey : arg.publicKey.toBuffer(),