diff --git a/platform/zoul/contiki-conf.h b/platform/zoul/contiki-conf.h
index 9b64554cb..229598b6d 100644
--- a/platform/zoul/contiki-conf.h
+++ b/platform/zoul/contiki-conf.h
@@ -323,7 +323,7 @@ typedef uint32_t rtimer_clock_t;
 
 /* Configure NullRDC for when it's selected */
 #define NULLRDC_CONF_802154_AUTOACK             1
-#define NULLRDC_CONF_802154_AUTOACK_HW			1
+#define NULLRDC_CONF_802154_AUTOACK_HW			    1
 
 /* Configure ContikiMAC for when it's selected */
 #define CONTIKIMAC_CONF_WITH_PHASE_OPTIMIZATION 0