diff --git a/fuzzers/005-tilegrid/add_tdb.py b/fuzzers/005-tilegrid/add_tdb.py
index b6e8cfa6..f351251c 100644
--- a/fuzzers/005-tilegrid/add_tdb.py
+++ b/fuzzers/005-tilegrid/add_tdb.py
@@ -113,7 +113,7 @@ def run(fn_in, fn_out, verbose=False):
         ("gtp_common", 32, 101),
         ("gtp_channel", 32, 22),
         ("gtx_common", 32, 101),
-        ("gtx_channel", 32, 22),
+        ("gtx_channel", 32, 6),
         ("clb_int", int_frames, int_words),
         ("iob_int", int_frames, int_words),
         ("iob18_int", int_frames, int_words),