diff --git a/firmware/hackrf_usb/usb_api_cpld.c b/firmware/hackrf_usb/usb_api_cpld.c
index e29007c5..cc9daa0f 100644
--- a/firmware/hackrf_usb/usb_api_cpld.c
+++ b/firmware/hackrf_usb/usb_api_cpld.c
@@ -40,6 +40,8 @@ volatile bool cpld_wait = false;
 
 static void cpld_buffer_refilled(void* user_data, unsigned int length)
 {
+	(void)user_data;
+	(void)length;
 	cpld_wait = false;
 }