diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 0ec82892..07721581 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -23,6 +23,7 @@ function TX(data, block) {
   this._hash = null;
   this._raw = data._raw || null;
   this._network = data._network || false;
+  this._lock = this.lock;
 
   if (data.inputs) {
     data.inputs.forEach(function(input) {
@@ -101,16 +102,18 @@ TX.prototype._input = function _input(i, index) {
     var prev = input.out.tx.outputs[input.out.index].script;
     var lock = bcoin.script.lockTime(prev);
     if (lock) {
-      // this.lock = Math.max(lock.toNumber(), this.lock);
-      if (this.lock === 0)
-        this.lock = lock.toNumber();
+      if (this._lock === 0)
+        this.lock = Math.max(lock.toNumber(), this.lock);
       if (!bcoin.script.spendable(this, this.lock))
         throw new Error('Cannot spend ' + utils.revHex(input.out.hash));
-      if (input.seq === 0xffffffff)
-        input.seq = 0;
     }
   }
 
+  if (this.lock !== 0) {
+    if (i.seq === undefined)
+      input.seq = 0;
+  }
+
   // Try modifying existing input first
   var index = this._inputIndex(hash, index);
   if (index !== -1) {