diff --git a/manifest.json b/manifest.json
index 30c8cd2..ea6666e 100644
--- a/manifest.json
+++ b/manifest.json
@@ -1,9 +1,9 @@
 {
-  "manifest_version": 3,
+  "manifest_version": 2,
   "name": "Archive.org Link Grabber",
   "version": "0.1.0",
   "description": "Filter and export archive.org /download links; copy or send to aria2 RPC.",
-  "action": {
+  "browser_action": {
     "default_title": "Archive.org Link Grabber",
     "default_popup": "src/popup/index.html"
   },
@@ -15,16 +15,16 @@
     "storage",
     "clipboardWrite",
     "activeTab",
-    "contextMenus"
-  ],
-  "host_permissions": [
+    "contextMenus",
     "https://archive.org/*",
     "http://localhost:6800/*",
     "https://localhost:6800/*"
   ],
   "background": {
-    "service_worker": "src/background/index.js",
-    "type": "module"
+    "scripts": [
+      "src/lib/aria2-bg.js",
+      "src/background/index.js"
+    ]
   },
   "content_scripts": [
     {
diff --git a/src/background/index.js b/src/background/index.js
index 93cec10..84dcd9b 100644
--- a/src/background/index.js
+++ b/src/background/index.js
@@ -1,4 +1,4 @@
-import { addUrisBatch } from "../lib/aria2.js";
+// In MV2 background, aria2 helpers are exposed on globalThis by src/lib/aria2-bg.js
 
 browser.runtime.onMessage.addListener(async (msg, sender) => {
   if (!msg || !msg.type) return;
@@ -9,7 +9,7 @@ browser.runtime.onMessage.addListener(async (msg, sender) => {
       return { ok: false, error: 'Missing endpoint or URIs' };
     }
     try {
-      const res = await addUrisBatch({ endpoint, secret, uris, options });
+      const res = await globalThis.addUrisBatch({ endpoint, secret, uris, options });
       return { ok: true, result: res };
     } catch (err) {
       return { ok: false, error: String(err && err.message || err) };
@@ -40,9 +40,8 @@ browser.contextMenus.onClicked.addListener(async (info, tab) => {
       lastCollected: { tabId: tab.id, url: tab.url, time: Date.now(), count },
       lastItems: items
     });
-    try { await browser.action.setBadgeBackgroundColor({ color: '#3b82f6', tabId: tab.id }); } catch (e) {}
-    try { await browser.action.setBadgeText({ text: count ? String(count) : '', tabId: tab.id }); } catch (e) {}
-    try { if (browser.action.openPopup) await browser.action.openPopup(); } catch (e) {}
+    try { await browser.browserAction.setBadgeBackgroundColor({ color: '#3b82f6' }); } catch (e) {}
+    try { await browser.browserAction.setBadgeText({ text: count ? String(count) : '' }); } catch (e) {}
   } catch (e) {
     // Swallow errors; context menu is best-effort
   }
diff --git a/src/lib/aria2-bg.js b/src/lib/aria2-bg.js
new file mode 100644
index 0000000..0e2051c
--- /dev/null
+++ b/src/lib/aria2-bg.js
@@ -0,0 +1,58 @@
+// Background-friendly (non-module) aria2 helpers
+// Exposes addUri, addUrisBatch, and getVersion on globalThis
+
+(function(){
+  function rpcCall(endpoint, body) {
+    return fetch(endpoint, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(body)
+    }).then(async (res) => {
+      if (!res.ok) {
+        const text = await res.text().catch(() => String(res.status));
+        throw new Error(`aria2 RPC error ${res.status}: ${text}`);
+      }
+      return res.json();
+    });
+  }
+
+  function addUri({ endpoint, secret, uri, options = {} }) {
+    const body = {
+      jsonrpc: "2.0",
+      id: "archive-org-link-grabber:" + Date.now(),
+      method: "aria2.addUri",
+      params: [
+        secret ? `token:${secret}` : undefined,
+        [uri],
+        options
+      ].filter(v => v !== undefined)
+    };
+    return rpcCall(endpoint, body);
+  }
+
+  async function addUrisBatch({ endpoint, secret, uris, options = {} }) {
+    const results = [];
+    for (const uri of uris) {
+      // eslint-disable-next-line no-await-in-loop
+      const r = await addUri({ endpoint, secret, uri, options });
+      results.push(r);
+    }
+    return results;
+  }
+
+  function getVersion({ endpoint, secret }) {
+    const body = {
+      jsonrpc: "2.0",
+      id: "archive-org-link-grabber:getVersion:" + Date.now(),
+      method: "aria2.getVersion",
+      params: [secret ? `token:${secret}` : undefined].filter(Boolean)
+    };
+    return rpcCall(endpoint, body);
+  }
+
+  // expose
+  globalThis.addUrisBatch = addUrisBatch;
+  globalThis.addUri = addUri;
+  globalThis.getVersion = getVersion;
+})();
+