diff --git a/selfdrive/car/hyundai/interface.py b/selfdrive/car/hyundai/interface.py
index 486ff3e389..72a12b0ba8 100644
--- a/selfdrive/car/hyundai/interface.py
+++ b/selfdrive/car/hyundai/interface.py
@@ -205,11 +205,9 @@ class CarInterface(CarInterfaceBase):
     ret = self.CS.update(self.cp, self.cp_cam)
     self.sp_update_params()
 
-    self.CS.button_events = [
-      *create_button_events(self.CS.cruise_buttons[-1], self.CS.prev_cruise_buttons, BUTTONS_DICT),
-      *create_button_events(self.CS.lfa_enabled, self.CS.prev_lfa_enabled, {1: ButtonType.altButton1}),
-      *create_button_events(self.CS.main_buttons[-1], self.CS.prev_main_buttons, {1: ButtonType.altButton3})
-    ]
+    self.CS.button_events.extend(create_button_events(self.CS.cruise_buttons[-1], self.CS.prev_cruise_buttons, BUTTONS_DICT))
+    self.CS.button_events.extend(create_button_events(self.CS.lfa_enabled, self.CS.prev_lfa_enabled, {1: ButtonType.altButton1}))
+    self.CS.button_events.extend(create_button_events(self.CS.main_buttons[-1], self.CS.prev_main_buttons, {1: ButtonType.altButton3}))
 
     self.CS.accEnabled = self.get_sp_v_cruise_non_pcm_state(ret, self.CS.accEnabled,
                                                             self.CS.button_events, c.vCruise)
diff --git a/selfdrive/car/mazda/interface.py b/selfdrive/car/mazda/interface.py
index 1ad62f4923..2bd4f71c78 100755
--- a/selfdrive/car/mazda/interface.py
+++ b/selfdrive/car/mazda/interface.py
@@ -40,11 +40,8 @@ class CarInterface(CarInterfaceBase):
     self.sp_update_params()
 
     # TODO: add button types for inc and dec
-    self.CS.button_events = [
-      *self.CS.button_events,
-      *create_button_events(self.CS.distance_button, self.CS.prev_distance_button, {1: ButtonType.gapAdjustCruise}),
-      *create_button_events(self.CS.lkas_enabled, self.CS.prev_lkas_enabled, {1: ButtonType.altButton1})
-    ]
+    self.CS.button_events.extend(create_button_events(self.CS.distance_button, self.CS.prev_distance_button, {1: ButtonType.gapAdjustCruise}))
+    self.CS.button_events.extend(create_button_events(self.CS.lkas_enabled, self.CS.prev_lkas_enabled, {1: ButtonType.altButton1}))
 
     self.CS.mads_enabled = self.get_sp_cruise_main_state(ret, self.CS)