diff --git a/litex/tools/litex_term.py b/litex/tools/litex_term.py
index c521c0f4e..0f56e5ebf 100755
--- a/litex/tools/litex_term.py
+++ b/litex/tools/litex_term.py
@@ -58,7 +58,7 @@ sfl_prompt_ack = b"\x06"
 sfl_magic_req = b"sL5DdSMmkekro\n"
 sfl_magic_ack = b"z6IHG7cYDID6o\n"
 
-sfl_payload_length = 255
+sfl_payload_length = 64 # FIXME: understand why 255 failing with USB-FIFO.
 
 # General commands
 sfl_cmd_abort       = b"\x00"