diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 45458bd9..0ec82892 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -101,11 +101,11 @@ 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 (!bcoin.script.spendable(this, this.lock))
-      //   throw new Error('Cannot spend ' + utils.revHex(input.out.hash));
+      // this.lock = Math.max(lock.toNumber(), this.lock);
+      if (this.lock === 0)
+        this.lock = lock.toNumber();
+      if (!bcoin.script.spendable(this, this.lock))
+        throw new Error('Cannot spend ' + utils.revHex(input.out.hash));
       if (input.seq === 0xffffffff)
         input.seq = 0;
     }