diff --git a/package-lock.json b/package-lock.json
index 58f093a..ce34126 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "peoplelib",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "peoplelib",
-      "version": "2.1.5",
+      "version": "2.1.6",
       "license": "MIT",
       "dependencies": {
         "foliate-js": "1.0.1",
diff --git a/package.json b/package.json
index f311d91..57a7550 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "peoplelib",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "description": "多源开放文献、电子书与本地书库客户端",
   "main": "main.js",
   "author": "peoplelib",
diff --git a/src/_test/sources.test.js b/src/_test/sources.test.js
index 747dd50..ad6f3bf 100644
--- a/src/_test/sources.test.js
+++ b/src/_test/sources.test.js
@@ -624,6 +624,53 @@ test('zlib: 移除当前会话的非内置镜像会清除旧会话', () => {
   }
 });
 
+test('zlib: 自定义镜像优先于旧会话记录的内置镜像', async () => {
+  const zlib = h.freshRequire('sources/zlib.js');
+  const auth = require('../sources/zlib-auth');
+  const orig = {
+    getCustomMirrors: auth.getCustomMirrors,
+    getSession: auth.getSession,
+    setSession: auth.setSession
+  };
+  auth.getCustomMirrors = () => ['https://custom.example'];
+  auth.getSession = () => ({ userId: '1', userKey: 'k', mirror: 'https://1lib.sk' });
+  auth.setSession = () => {};
+  try {
+    h.resetCalls();
+    h.setHandler((url) => {
+      assert.ok(url.startsWith('https://custom.example/'), `先请求了旧会话镜像：${url}`);
+      return h.makeResponse({ body: { success: 1, books: [] } });
+    });
+    await zlib.list(1);
+    assert.strictEqual(h.getCalls().length, 1, '自定义镜像成功后仍请求了内置镜像');
+  } finally {
+    Object.assign(auth, orig);
+  }
+});
+
+test('zlib: 全部失败时保留自定义镜像的首要错误', async () => {
+  const zlib = h.freshRequire('sources/zlib.js');
+  const auth = require('../sources/zlib-auth');
+  const orig = {
+    getCustomMirrors: auth.getCustomMirrors,
+    getSession: auth.getSession
+  };
+  auth.getCustomMirrors = () => ['https://custom.example'];
+  auth.getSession = () => ({ userId: '1', userKey: 'k', mirror: 'https://1lib.sk' });
+  try {
+    h.setHandler((url) => {
+      if (url.startsWith('https://custom.example/')) throw new Error('请求超时，站点无响应');
+      throw new Error('该镜像返回了非预期内容');
+    });
+    await assert.rejects(
+      zlib.list(1),
+      /自定义镜像失败：请求超时，站点无响应；其余 \d+ 个镜像也未成功/
+    );
+  } finally {
+    Object.assign(auth, orig);
+  }
+});
+
 // 实测：会话过期时 /file 返回 400 + {"success":0,"error":"Please login"}。
 // 若按 HTTP 状态码短路，真实原因会被吞掉，自动重登也不会触发。
 test('zlib: 4xx+JSON 的会话过期能被识别并自动重新登录', async () => {
diff --git a/src/sources/zlib.js b/src/sources/zlib.js
index dfad890..5e601d9 100644
--- a/src/sources/zlib.js
+++ b/src/sources/zlib.js
@@ -215,12 +215,17 @@ async function callOn(mirror, path, params, session, method) {
 }
 
 async function attempt(session, path, params, method) {
+  const custom = auth.getCustomMirrors();
   const mirrors = getMirrors();
-  const ordered = session.mirror
+  // 用户显式配置镜像后必须严格优先于旧会话镜像，否则界面写着“自定义优先”，
+  // 实际却仍先等待上次成功但现在已失效的默认域名。
+  const ordered = custom.length
+    ? mirrors
+    : session.mirror
     ? [session.mirror, ...mirrors.filter((m) => m !== session.mirror)]
     : mirrors;
 
-  let lastErr;
+  const errors = [];
   for (const m of ordered) {
     try {
       const j = await callOn(m, path, params, session, method);
@@ -228,10 +233,18 @@ async function attempt(session, path, params, method) {
       return { ok: true, data: j };
     } catch (e) {
       if (e.code === 'AUTH_STALE') return { ok: false, stale: true, error: e };
-      lastErr = e;
+      errors.push(e);
     }
   }
-  return { ok: false, stale: false, error: lastErr };
+  if (errors.length <= 1) {
+    return { ok: false, stale: false, error: errors[0] };
+  }
+  const first = errors[0];
+  const label = custom.length ? '自定义镜像失败' : '首选镜像失败';
+  const summary = new Error(
+    `${label}：${(first && first.message) || String(first)}；其余 ${errors.length - 1} 个镜像也未成功`
+  );
+  return { ok: false, stale: false, error: summary };
 }
 
 async function apiCall(path, params = {}, method = 'GET') {