diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index 795f79aa..c65ee44c 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -22,8 +22,6 @@ function Block(data, subtype) {
   if (!(this instanceof Block))
     return new Block(data, subtype);
 
-  assert(typeof data.hash !== 'string');
-
   this.type = 'block';
   this.subtype = subtype || data.subtype;
   this.version = data.version;
@@ -235,6 +233,18 @@ Block.prototype.getMerkleRoot = function getMerkleRoot() {
   return utils.toHex(tree[tree.length - 1]);
 };
 
+Block.prototype.getMerkleRoot = function getMerkleRoot() {
+  var hashes = [];
+  var i;
+
+  assert(this.subtype === 'block');
+
+  for (i = 0; i < this.txs.length; i++)
+    hashes.push(this.txs[i].hash());
+
+  return utils.getMerkleRoot(hashes);
+};
+
 Block.prototype._verify = function _verify() {
   var uniq = {};
   var i, tx, hash;
diff --git a/lib/bcoin/ec.js b/lib/bcoin/ec.js
index c09b786b..e218f5b3 100644
--- a/lib/bcoin/ec.js
+++ b/lib/bcoin/ec.js
@@ -38,6 +38,10 @@ ec.random = function random(size) {
   return new Buffer(elliptic.rand(size));
 };
 
+bn.prototype.toBuffer = function toBuffer(order, size) {
+  return new Buffer(this.toArray(order, size));
+};
+
 ec.verify = function verify(msg, sig, key, historical) {
   if (key.getPublicKey)
     key = key.getPublicKey();
diff --git a/lib/bcoin/protocol/framer.js b/lib/bcoin/protocol/framer.js
index 32ff134a..d95bfea7 100644
--- a/lib/bcoin/protocol/framer.js
+++ b/lib/bcoin/protocol/framer.js
@@ -403,7 +403,9 @@ Framer.block = function _block(block, type) {
     p = new Buffer(80 + utils.sizeIntv(block.txs.length));
   } else {
     for (i = 0; i < block.txs.length; i++) {
-      tx = block.txs[i].render();
+      tx = block.txs[i].render
+        ? block.txs[i].render()
+        : Framer.tx(block.txs[i]);
       txs.push(tx);
       txSize += tx.length;
     }
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 720a8a6d..5ac1f6cb 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -22,8 +22,6 @@ function TX(data, block) {
   if (!data)
     data = {};
 
-  assert(typeof data.hash !== 'string');
-
   this.type = 'tx';
   this.version = data.version || 1;
   this.inputs = [];
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index ed669904..a6352dfb 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -1587,3 +1587,38 @@ utils.once = function once(callback) {
 
   return onceFn;
 };
+
+utils.buildMerkleTree = function buildMerkleTree(items) {
+  var tree = items.slice();
+  var i, j, size, i2, hash;
+
+  j = 0;
+  size = items.length;
+
+  for (; size > 1; size = ((size + 1) / 2) | 0) {
+    for (i = 0; i < size; i += 2) {
+      i2 = Math.min(i + 1, size - 1);
+      if (i2 === i + 1 && i2 + 1 === size
+          && tree[j + i] === tree[j + i2]) {
+        return;
+      }
+      hash = Buffer.concat([tree[j + i], tree[j + i2]]);
+      hash = utils.dsha256(hash);
+      tree.push(hash);
+    }
+    j += size;
+  }
+
+  if (!tree.length)
+    return;
+
+  return tree;
+};
+
+utils.getMerkleRoot = function getMerkleRoot(items) {
+  var tree = utils.buildMerkleTree(items);
+  if (!tree)
+    return;
+
+  return utils.toHex(tree[tree.length - 1]);
+};