diff --git a/src/drivers/driver_nl80211_event.c b/src/drivers/driver_nl80211_event.c
index 5c103a4..29893a4 100644
--- a/src/drivers/driver_nl80211_event.c
+++ b/src/drivers/driver_nl80211_event.c
@@ -2923,8 +2923,8 @@
 	data.bss_color_collision.bitmap =
 		nla_get_u64(tb[NL80211_ATTR_OBSS_COLOR_BITMAP]);
 
-	wpa_printf(MSG_DEBUG, "nl80211: BSS color collision - bitmap %08lx",
-		   data.bss_color_collision.bitmap);
+	wpa_printf(MSG_DEBUG, "nl80211: BSS color collision - bitmap %08llx",
+		   (long long unsigned int) data.bss_color_collision.bitmap);
 	wpa_supplicant_event(drv->ctx, EVENT_BSS_COLOR_COLLISION, &data);
 }