diff --git a/src/l2cap_signaling.c b/src/l2cap_signaling.c
index 44fd814ef..bcaa3f485 100644
--- a/src/l2cap_signaling.c
+++ b/src/l2cap_signaling.c
@@ -42,6 +42,7 @@
 
 #include "l2cap_signaling.h"
 #include "btstack-config.h"
+#include "hci.h"
 
 #include <string.h>