diff --git a/lib/bcoin/writer.js b/lib/bcoin/writer.js
index bec886bd..025f1237 100644
--- a/lib/bcoin/writer.js
+++ b/lib/bcoin/writer.js
@@ -103,7 +103,7 @@ BufferWriter.prototype.render = function render(keep) {
         off += utils.checksum(data.slice(0, off)).copy(data, off);
         break;
       case FILL:
-        item[1].fill(item[1], off, off + item[2]);
+        data.fill(item[1], off, off + item[2]);
         off += item[2];
         break;
       default:
@@ -438,6 +438,10 @@ BufferWriter.prototype.writeChecksum = function writeChecksum() {
 
 BufferWriter.prototype.fill = function fill(value, size) {
   assert(size >= 0);
+
+  if (size === 0)
+    return;
+
   this.written += size;
   this.data.push([FILL, value, size]);
 };