diff --git a/src/btstack_linked_list.c b/src/btstack_linked_list.c
index e294ab781..e3cf65e08 100644
--- a/src/btstack_linked_list.c
+++ b/src/btstack_linked_list.c
@@ -73,29 +73,31 @@ btstack_linked_item_t * btstack_linked_list_get_last_item(btstack_linked_list_t
 /**
  * btstack_linked_list_add
  */
-void btstack_linked_list_add(btstack_linked_list_t * list, btstack_linked_item_t *item){        // <-- add item to list
+bool btstack_linked_list_add(btstack_linked_list_t * list, btstack_linked_item_t *item){        // <-- add item to list
     // check if already in list
     btstack_linked_item_t *it;
     for (it = *list; it ; it = it->next){
         if (it == item) {
-            return;
+            return false;
         }
     }
     // add first
     item->next = *list;
     *list = item;
+    return true;
 }
 
-void btstack_linked_list_add_tail(btstack_linked_list_t * list, btstack_linked_item_t *item){   // <-- add item to list as last element
+bool btstack_linked_list_add_tail(btstack_linked_list_t * list, btstack_linked_item_t *item){   // <-- add item to list as last element
     // check if already in list
     btstack_linked_item_t *it;
     for (it = (btstack_linked_item_t *) list; it->next ; it = it->next){
         if (it->next == item) {
-            return;
+            return false;
         }
     }
     item->next = (btstack_linked_item_t*) 0;
     it->next = item;
+    return true;
 }
 
 int  btstack_linked_list_remove(btstack_linked_list_t * list, btstack_linked_item_t *item){    // <-- remove item from list
diff --git a/src/btstack_linked_list.h b/src/btstack_linked_list.h
index f9137475d..6d6712d58 100644
--- a/src/btstack_linked_list.h
+++ b/src/btstack_linked_list.h
@@ -74,15 +74,17 @@ bool btstack_linked_list_empty(btstack_linked_list_t * list);
  * @brief Add item to list as first element.
  * @param list
  * @param item
+ * @returns true if item was added, false if item already in list
  */
-void btstack_linked_list_add(btstack_linked_list_t * list, btstack_linked_item_t *item);       
+bool btstack_linked_list_add(btstack_linked_list_t * list, btstack_linked_item_t *item);
 
 /**
  * @brief Add item to list as last element.
  * @param list
  * @param item
+ * @returns true if item was added, false if item already in list
  */
-void btstack_linked_list_add_tail(btstack_linked_list_t * list, btstack_linked_item_t *item);
+bool btstack_linked_list_add_tail(btstack_linked_list_t * list, btstack_linked_item_t *item);
 
 /**
  * @brief Pop (get + remove) first element.