diff --git a/ports/stm32/pin.c b/ports/stm32/pin.c
index fbd3f00c17..4d7a8aefaa 100644
--- a/ports/stm32/pin.c
+++ b/ports/stm32/pin.c
@@ -452,7 +452,7 @@ STATIC mp_obj_t pin_names(mp_obj_t self_in) {
     mp_obj_t result = mp_obj_new_list(0, NULL);
     mp_obj_list_append(result, MP_OBJ_NEW_QSTR(self->name));
 
-    mp_map_t *map = mp_obj_dict_get_map((mp_obj_t)&pin_board_pins_locals_dict);
+    const mp_map_t *map = &pin_board_pins_locals_dict.map;
     mp_map_elem_t *elem = map->table;
 
     for (mp_uint_t i = 0; i < map->used; i++, elem++) {
diff --git a/ports/stm32/pin_named_pins.c b/ports/stm32/pin_named_pins.c
index 726da54dd6..893fc8b4e8 100644
--- a/ports/stm32/pin_named_pins.c
+++ b/ports/stm32/pin_named_pins.c
@@ -44,8 +44,8 @@ const mp_obj_type_t pin_board_pins_obj_type = {
 };
 
 const pin_obj_t *pin_find_named_pin(const mp_obj_dict_t *named_pins, mp_obj_t name) {
-    mp_map_t *named_map = mp_obj_dict_get_map((mp_obj_t)named_pins);
-    mp_map_elem_t *named_elem = mp_map_lookup(named_map, name, MP_MAP_LOOKUP);
+    const mp_map_t *named_map = &named_pins->map;
+    mp_map_elem_t *named_elem = mp_map_lookup((mp_map_t*)named_map, name, MP_MAP_LOOKUP);
     if (named_elem != NULL && named_elem->value != NULL) {
         return named_elem->value;
     }