diff --git a/Internal.h b/Internal.h
index 253eb45..8116f01 100644
--- a/Internal.h
+++ b/Internal.h
@@ -645,8 +645,7 @@ struct TestDriver {
 
   bool ok = true;
 
-  // const int prefixLen = arbitrary->bounded(512);
-  const int prefixLen = 0;
+  const int prefixLen = arbitrary->bounded(512);
   const int prefixByte = arbitrary->randT<uint8_t>();
 
   // Call until it returns true, for "done". Check internal invariants etc