diff --git a/stmhal/can.c b/stmhal/can.c
index 9b8f2a071508429de81e0a3e4492c7d48a92bbb9..09861ec73acb53e5cde96bb0c8e5deeeb59613a1 100644
--- a/stmhal/can.c
+++ b/stmhal/can.c
@@ -631,8 +631,8 @@ STATIC mp_obj_t pyb_can_setfilter(mp_uint_t n_args, const mp_obj_t *pos_args, mp
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
-    mp_uint_t len;
-    mp_uint_t rtr_len;
+    size_t len;
+    size_t rtr_len;
     mp_uint_t rtr_masks[4] = {0, 0, 0, 0};
     mp_obj_t *rtr_flags;
     mp_obj_t *params;
diff --git a/stmhal/modutime.c b/stmhal/modutime.c
index 7f2c549bd7405a28bfd6a179aeaa37d11c146d5e..2c7245080331ed1676449d191f03f1fb5b8b1d98 100644
--- a/stmhal/modutime.c
+++ b/stmhal/modutime.c
@@ -100,7 +100,7 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(time_localtime_obj, 0, 1, time_localtime);
 /// the number of seconds since Jan 1, 2000.
 STATIC mp_obj_t time_mktime(mp_obj_t tuple) {
 
-    mp_uint_t len;
+    size_t len;
     mp_obj_t *elem;
 
     mp_obj_get_array(tuple, &len, &elem);