diff --git a/bin/mbus-serial-switch-baudrate.c b/bin/mbus-serial-switch-baudrate.c
index 0a90f95..426526d 100644
--- a/bin/mbus-serial-switch-baudrate.c
+++ b/bin/mbus-serial-switch-baudrate.c
@@ -48,7 +48,7 @@ main(int argc, char **argv)
     }
     else
     {
-        fprintf(stderr, "usage: %s device address target-baudrate\n", argv[0]);
+        fprintf(stderr, "usage: %s [-b BAUDRATE] device address target-baudrate\n", argv[0]);
         return 0;
     }