diff --git a/tmk_core/common/action_layer.h b/tmk_core/common/action_layer.h
index 785bb5be4446..d89ed6e5ce8e 100644
--- a/tmk_core/common/action_layer.h
+++ b/tmk_core/common/action_layer.h
@@ -27,10 +27,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 extern uint32_t default_layer_state;
 void default_layer_debug(void);
-uint32_t default_layer_set(uint32_t state);
+void default_layer_set(uint32_t state);
 
 __attribute__((weak))
-void default_layer_state_set_kb(uint32_t state);
+uint32_t default_layer_state_set_kb(uint32_t state);
 
 #ifndef NO_ACTION_LAYER
 /* bitwise operation */