diff --git a/shared-bindings/nvm/ByteArray.c b/shared-bindings/nvm/ByteArray.c
index be01c1f706414..b278300626737 100644
--- a/shared-bindings/nvm/ByteArray.c
+++ b/shared-bindings/nvm/ByteArray.c
@@ -35,7 +35,7 @@
 //|
 static mp_obj_t nvm_bytearray_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
     nvm_bytearray_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    uint16_t len = common_hal_nvm_bytearray_get_length(self);
+    uint32_t len = common_hal_nvm_bytearray_get_length(self);
     switch (op) {
         case MP_UNARY_OP_BOOL:
             return mp_obj_new_bool(len != 0);