diff --git a/stm-firmware/shell.c b/stm-firmware/shell.c
index c48c946..dbc08c8 100644
--- a/stm-firmware/shell.c
+++ b/stm-firmware/shell.c
@@ -51,6 +51,7 @@ static char IN_SECTION(.ccm.bss) history_buffer[600];
 
 static bool check_opt(const char *args, uint32_t len, const char *opt_to_check)
 {
+	(void)len;
 	char str[128];
 	const char *ptr;
 	static const char * const tokens = "\t ";