diff --git a/packages/hydrooj/src/model/problem.ts b/packages/hydrooj/src/model/problem.ts
index bcd4fc8b4..60e9239f8 100644
--- a/packages/hydrooj/src/model/problem.ts
+++ b/packages/hydrooj/src/model/problem.ts
@@ -6,7 +6,9 @@ import * as document from './document';
 import domain from './domain';
 import { buildProjection } from '../utils';
 import type { ProblemStatusDoc, Pdict, Document } from '../interface';
-import { ArrayKeys, NumberKeys, Projection } from '../typeutils';
+import {
+    ArrayKeys, MaybeArray, NumberKeys, Projection,
+} from '../typeutils';
 import { ProblemNotFoundError, ValidationError } from '../error';
 import storage from '../service/storage';
 import * as bus from '../service/bus';
@@ -149,7 +151,7 @@ export class ProblemModel {
         const names = (name instanceof Array) ? name : [name];
         await storage.del(names.map((t) => `problem/${domainId}/${pid}/testdata/${t}`));
         await ProblemModel.pull(domainId, pid, 'data', names);
-        await bus.emit('problem/delTestdata', domainId, pid, name);
+        await bus.emit('problem/delTestdata', domainId, pid, names);
     }
 
     static async addAdditionalFile(domainId: string, pid: number, name: string, f: Readable | Buffer | string) {
@@ -164,11 +166,11 @@ export class ProblemModel {
         await bus.emit('problem/addAdditionalFile', domainId, pid, name, payload);
     }
 
-    static async delAdditionalFile(domainId: string, pid: number, name: string | string[]) {
+    static async delAdditionalFile(domainId: string, pid: number, name: MaybeArray<string>) {
         const names = (name instanceof Array) ? name : [name];
         await storage.del(names.map((t) => `problem/${domainId}/${pid}/additional_file/${t}`));
         await ProblemModel.pull(domainId, pid, 'additional_file', names);
-        await bus.emit('problem/delAdditionalFile', domainId, pid, name);
+        await bus.emit('problem/delAdditionalFile', domainId, pid, names);
     }
 
     static async random(domainId: string, query: FilterQuery<Pdoc>): Promise<string | null> {
@@ -255,7 +257,7 @@ ProblemModel.extend((docId, pid) => ({
     data: [],
     additional_file: [],
     hidden: true,
-    config: {},
+    config: '',
     acMsg: '',
     difficulty: 0,
 }));
diff --git a/packages/hydrooj/src/service/bus.ts b/packages/hydrooj/src/service/bus.ts
index 7bf119ca7..9aa051167 100644
--- a/packages/hydrooj/src/service/bus.ts
+++ b/packages/hydrooj/src/service/bus.ts
@@ -79,10 +79,10 @@ export interface EventMap extends Record<string, any> {
     'problem/list': (query: FilterQuery<Pdoc>, handler: any) => VoidReturn
     'problem/get': (doc: Pdoc, handler: any) => VoidReturn
     'problem/delete': (domainId: string, docId: number) => VoidReturn
-    'problem/addTestdata': (domainId: string, docId: number, name: string, payload: FileInfo) => VoidReturn
-    'problem/delTestdata': (domainId: string, docId: number, name: string) => VoidReturn
-    'problem/addAdditionalFile': (domainId: string, docId: number, name: string, payload: FileInfo) => VoidReturn
-    'problem/delAdditionalFile': (domainId: string, docId: number, name: string) => VoidReturn
+    'problem/addTestdata': (domainId: string, docId: number, name: string, payload: Omit<FileInfo, '_id'>) => VoidReturn
+    'problem/delTestdata': (domainId: string, docId: number, name: string[]) => VoidReturn
+    'problem/addAdditionalFile': (domainId: string, docId: number, name: string, payload: Omit<FileInfo, '_id'>) => VoidReturn
+    'problem/delAdditionalFile': (domainId: string, docId: number, name: string[]) => VoidReturn
 
     'training/list': (query: FilterQuery<TrainingDoc>, handler: any) => VoidReturn
     'training/get': (tdoc: TrainingDoc, handler: any) => VoidReturn
diff --git a/packages/hydrooj/src/upgrade.ts b/packages/hydrooj/src/upgrade.ts
index 1a6d67996..bd3ddc2b1 100644
--- a/packages/hydrooj/src/upgrade.ts
+++ b/packages/hydrooj/src/upgrade.ts
@@ -138,7 +138,10 @@ const scripts: UpgradeScript[] = [
                 storage.list(`problem/${pdoc.domainId}/${pdoc.docId}/testdata/`),
                 storage.list(`problem/${pdoc.domainId}/${pdoc.docId}/additional_file/`),
             ]);
-            await problem.edit(pdoc.domainId, pdoc.docId, { data, additional_file });
+            await problem.edit(
+                pdoc.domainId, pdoc.docId,
+                { data: data.map((d) => ({ ...d, _id: d.name })), additional_file: additional_file.map((d) => ({ ...d, _id: d.name })) },
+            );
             if (!pdoc.config) return;
             if (data.map((d) => d.name).includes('config.yaml')) return;
             const cfg = yaml.dump(pdoc.config);
diff --git a/packages/migrate-hustoj/script.ts b/packages/migrate-hustoj/script.ts
index 689f2715e..5a7eee513 100644
--- a/packages/migrate-hustoj/script.ts
+++ b/packages/migrate-hustoj/script.ts
@@ -100,7 +100,7 @@ export async function run({
             await problem.edit('system', pid, {
                 nAccept: pdoc.accepted,
                 nSubmit: pdoc.submit,
-                config: { time: `${pdoc.time_limit}s`, memory: `${pdoc.memory_limit}m` },
+                config: `time: ${pdoc.time_limit}s\nmemory: ${pdoc.memory_limit}m`,
                 owner: uidMap[cdoc[0].user_id],
             });
         }