diff --git a/xmodem.options b/xmodem.options
index 3593126..3af6125 100644
--- a/xmodem.options
+++ b/xmodem.options
@@ -2,5 +2,5 @@
 # https://jpa.kapsi.fi/nanopb/docs/reference.html#proto-file-options
 
 *XModem.buffer max_size:128
-*XModem.seq int_size:8
+*XModem.seq int_size:16
 *XModem.crc16 int_size:16