diff --git a/lib/bcoin/input.js b/lib/bcoin/input.js
index 37557e9d..28952098 100644
--- a/lib/bcoin/input.js
+++ b/lib/bcoin/input.js
@@ -32,7 +32,7 @@ var BufferWriter = require('./writer');
 
 function Input(options, mutable) {
   if (!(this instanceof Input))
-    return new Input(options);
+    return new Input(options, mutable);
 
   assert(options, 'Input data is required.');
 
diff --git a/lib/bcoin/output.js b/lib/bcoin/output.js
index 0e054ae2..798537a8 100644
--- a/lib/bcoin/output.js
+++ b/lib/bcoin/output.js
@@ -29,7 +29,7 @@ function Output(options, mutable) {
   var value;
 
   if (!(this instanceof Output))
-    return new Output(options);
+    return new Output(options, mutable);
 
   assert(options, 'Output data is required.');
 
@@ -43,7 +43,7 @@ function Output(options, mutable) {
   this.script = bcoin.script(options.script, this.mutable);
 
   assert(typeof this.value === 'number');
-  assert(!this.mutable || this.value > 0);
+  assert(!this.mutable || this.value >= 0);
 }
 
 /**
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 689576a5..a7f56969 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -39,7 +39,7 @@ function Witness(items, mutable) {
   }
 
   if (!(this instanceof Witness))
-    return new Witness(items);
+    return new Witness(items, mutable);
 
   this.mutable = !!mutable;
 
@@ -818,7 +818,7 @@ function Script(code, mutable) {
   }
 
   if (!(this instanceof Script))
-    return new Script(code);
+    return new Script(code, mutable);
 
   this.mutable = !!mutable;
 
diff --git a/test/chain-test.js b/test/chain-test.js
index efa2c371..3cb38dbd 100644
--- a/test/chain-test.js
+++ b/test/chain-test.js
@@ -40,6 +40,7 @@ describe('Chain', function() {
           value: utils.satoshi('25.0')
         });
         redeemer.addInput(tx, 0);
+        redeemer.setLocktime(chain.height);
         wallet.sign(redeemer);
         attempt.addTX(redeemer);
       }