diff --git a/src/js/game/components/belt_reader.js b/src/js/game/components/belt_reader.js
index b8ca0736..d59feb9c 100644
--- a/src/js/game/components/belt_reader.js
+++ b/src/js/game/components/belt_reader.js
@@ -1,6 +1,7 @@
 import { Component } from "../component";
 import { BaseItem } from "../base_item";
 import { typeItemSingleton } from "../item_resolver";
+import { types } from "../../savegame/serialization";
 
 export class BeltReaderComponent extends Component {
     static getId() {
@@ -13,7 +14,7 @@ export class BeltReaderComponent extends Component {
 
     static getSchema() {
         return {
-            lastItem: typeItemSingleton,
+            lastItem: types.nullable(typeItemSingleton),
         };
     }