diff --git a/py/objarray.c b/py/objarray.c
index e3a59a0f89cfaa72ebdf5c3987fa3850bd1bc288..30613fcb6e4b1b0d5b6c5c4a9c857103de9b2b01 100644
--- a/py/objarray.c
+++ b/py/objarray.c
@@ -54,7 +54,7 @@
 #if MICROPY_PY_BUILTINS_MEMORYVIEW
 #define TYPECODE_MASK (0x7f)
 #else
-#define TYPECODE_MASK (~(mp_uint_t)1)
+#define TYPECODE_MASK (~(mp_uint_t)0)
 #endif
 
 typedef struct _mp_obj_array_t {