diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index aaf1d7ba..56bb1347 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -1087,7 +1087,7 @@ script.bool = function bool(value) {
   return false;
 };
 
-script.num = function num(value, useNum, minimaldata) {
+script.num = function num(value, useNum, flags) {
   if (utils.isFinite(value))
     return useNum ? value : new bn(value, 'le');
 
@@ -1097,7 +1097,7 @@ script.num = function num(value, useNum, minimaldata) {
 
   assert(Buffer.isBuffer(value));
 
-  if (minimaldata && value.length > 0) {
+  if ((flags & constants.flags.VERIFY_MINIMALDATA) && value.length > 0) {
     // If the low bits on the last byte are unset,
     // fail if The value's second to last byte does
     // not have the high bit set. A number can't
@@ -1115,10 +1115,6 @@ script.num = function num(value, useNum, minimaldata) {
     }
   }
 
-  // Optimize by avoiding big numbers
-  if (useNum && value.length <= 1)
-    return value.length === 0 ? 0 : value[0];
-
   // If we are signed, do (~num + 1) to get
   // the positive counterpart and set bn's
   // negative flag.
@@ -1129,6 +1125,9 @@ script.num = function num(value, useNum, minimaldata) {
       value = new bn(value, 'le').notn(value.length * 8).addn(1).neg();
     }
   } else {
+    // Optimize by avoiding big numbers
+    if (useNum && value.length <= 1)
+      return value.length === 0 ? 0 : value[0];
     value = new bn(value, 'le');
   }
 
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index e0a89fcb..d750b306 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -966,14 +966,17 @@ utils.nonce = function nonce() {
 
 utils.isNegZero = function isNegZero(bytes, order) {
   var s = 0;
+  var b, res;
 
   if (order === 'le')
     s = bytes.length - 1;
 
   if (bytes[s] & 0x80) {
-    bytes = bytes.slice();
+    b = bytes[s];
     bytes[s] &= ~0x80;
-    return new bn(bytes, order).cmpn(0) === 0;
+    res = new bn(bytes, order).cmpn(0) === 0;
+    bytes[s] = b;
+    return res;
   }
 
   return false;