diff --git a/f4jumble_long.py b/f4jumble_long.py
index 2b1553c..f8af499 100755
--- a/f4jumble_long.py
+++ b/f4jumble_long.py
@@ -31,7 +31,7 @@ def main():
         'f4jumble_long',
         (
             ('length', 'usize'),
-            ('jumbled_hash', 'Vec<u8>'),
+            ('jumbled_hash', '[u8; 64]'),
         ),
         hashed_test_vectors,
     )