diff --git a/py/objarray.c b/py/objarray.c
index ac4e343d06..75bc671c16 100644
--- a/py/objarray.c
+++ b/py/objarray.c
@@ -191,7 +191,10 @@ static mp_obj_t bytearray_make_new(const mp_obj_type_t *type_in, size_t n_args,
         // 1 arg, an integer: construct a blank bytearray of that length
         mp_uint_t len = mp_obj_get_int(args[0]);
         mp_obj_array_t *o = array_new(BYTEARRAY_TYPECODE, len);
+        // If this config is set then the GC clears all memory, so we don't need to.
+        #if !MICROPY_GC_CONSERVATIVE_CLEAR
         memset(o->items, 0, len);
+        #endif
         return MP_OBJ_FROM_PTR(o);
     } else {
         // 1 arg: construct the bytearray from that