diff --git a/package-lock.json b/package-lock.json
index 0dcbac5..6b6e28a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "mrterm",
-  "version": "0.13.2",
+  "version": "0.13.3",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mrterm",
-      "version": "0.13.2",
+      "version": "0.13.3",
       "license": "MIT",
       "dependencies": {
         "@xterm/addon-fit": "^0.11.0",
diff --git a/package.json b/package.json
index 20fff73..f1943da 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "mrterm",
   "productName": "MrTerm",
-  "version": "0.13.2",
+  "version": "0.13.3",
   "description": "Moderner SSH-, SFTP- und RDP-Client",
   "main": "src/main/main.js",
   "author": "MrBlake",
diff --git a/src/main/ctap2.js b/src/main/ctap2.js
index c76eaf9..33b6aa7 100644
--- a/src/main/ctap2.js
+++ b/src/main/ctap2.js
@@ -210,4 +210,48 @@ async function makeCredential(ui, { timeoutMs = 60000 } = {}) {
   }
 }
 
-module.exports = { makeCredential, CtapError, CANCEL_CODES, PIN };
+// Entspricht WebAuthn-PRF (evalByCredential) über hmac-secret, ohne PIN (wie Chromium mit
+// userVerification "discouraged"). creds: [{ credId: Buffer, salt: Buffer }] – salt ist der rohe PRF-Eingabewert.
+// Liefert { credId: Buffer, secret: Buffer(32) }, oder null, wenn kein FIDO2-Gerät per hidraw erreichbar ist.
+async function getHmacSecret(ui, creds, { timeoutMs = 60000 } = {}) {
+  let dev;
+  try { dev = Device.open(); } catch { return null; }
+  if (!dev) return null;
+  let timer;
+  try {
+    await dev.init();
+    const info = await dev.cbor(0x04);
+    if (!(info.get(1) || []).some((v) => String(v).startsWith('FIDO_2'))) return null;
+    const rpId = 'localhost';
+    const desc = (c) => new Map([['id', c.credId], ['type', 'public-key']]);
+    // Welches Credential liegt auf diesem Schlüssel? (Vorabprüfung ohne Berühren, up=false)
+    let cred = null;
+    for (const c of creds) {
+      try {
+        await dev.cbor(0x02, new Map([[1, rpId], [2, crypto.randomBytes(32)], [3, [desc(c)]], [5, new Map([['up', false]])]]));
+        cred = c; break;
+      } catch (e) { if (e.code !== 0x2e) throw e; }
+    }
+    if (!cred) throw new CtapError(0x2e);
+    const { key, platformKey } = await sharedSecret(dev);
+    const salt = crypto.createHash('sha256').update(Buffer.concat([Buffer.from('WebAuthn PRF\0', 'latin1'), cred.salt])).digest();
+    const saltEnc = aes('enc', key, salt);
+    const saltAuth = crypto.createHmac('sha256', key).update(saltEnc).digest().subarray(0, 16);
+    ui.touch(() => dev.cancel());
+    timer = setTimeout(() => dev.cancel(), timeoutMs);
+    const r = await dev.cbor(0x02, new Map([
+      [1, rpId], [2, crypto.randomBytes(32)], [3, [desc(cred)]],
+      [4, new Map([['hmac-secret', new Map([[1, platformKey], [2, saltEnc], [3, saltAuth]])]])],
+    ]));
+    const authData = r.get(2);
+    if (!(authData[32] & 0x80)) throw new CtapError(-1);
+    const ext = dec(authData, 37)[0].get('hmac-secret');
+    if (!ext) throw new CtapError(-1);
+    return { credId: Buffer.from(cred.credId), secret: aes('dec', key, ext).subarray(0, 32) };
+  } finally {
+    clearTimeout(timer);
+    dev.close();
+  }
+}
+
+module.exports = { makeCredential, getHmacSecret, CtapError, CANCEL_CODES, PIN };
diff --git a/src/main/fido.js b/src/main/fido.js
index d7338e1..95720b9 100644
--- a/src/main/fido.js
+++ b/src/main/fido.js
@@ -99,6 +99,26 @@ async function registerNative(parent) {
   }
 }
 
+// PRF-Abfrage direkt per CTAP2 (Linux); null, wenn kein FIDO2-Gerät per hidraw erreichbar ist
+async function deriveNative(parent, creds, text) {
+  const w = await openWindow(parent, text || i18n.t('Touch your security key to unlock MrTerm.'));
+  let abort = () => {};
+  let cancelled = false;
+  w.once('closed', () => { cancelled = true; abort(); });
+  try {
+    const r = await ctap2.getHmacSecret({ touch(a) { abort = a; if (cancelled) a(); } },
+      creds.map((c) => ({ credId: Buffer.from(c.credId, 'base64url'), salt: Buffer.from(c.prfSalt, 'base64url') })));
+    return r && { credId: b64url(r.credId), secret: r.secret };
+  } catch (e) {
+    if (cancelled || ctap2.CANCEL_CODES.has(e.code)) throw new Error(i18n.t('Security key prompt was cancelled or timed out.'));
+    if (e.code === 0x2e) throw new Error(i18n.t('Unknown security key.'));
+    if (e.code === -1) throw new Error(i18n.t('This security key does not support the hmac-secret/PRF extension.'));
+    throw e;
+  } finally {
+    if (!w.isDestroyed()) w.destroy();
+  }
+}
+
 const b64url = (buf) => Buffer.from(buf).toString('base64url');
 
 // Neuen Schlüssel registrieren; liefert die Credential-ID (base64url)
@@ -124,6 +144,10 @@ async function register(parent) {
 // PRF-Wert für einen der Schlüssel abfragen. creds: [{ credId, prfSalt }] (base64url)
 // Liefert { credId, secret: Buffer(32) }
 async function derive(parent, creds, text) {
+  if (process.platform === 'linux') {
+    const r = await deriveNative(parent, creds, text);
+    if (r) return r;
+  }
   const r = await ceremony(parent, text || i18n.t('Touch your security key to unlock MrTerm.'), `
     const creds = ${JSON.stringify(creds)};
     const evalByCredential = Object.fromEntries(creds.map((c) => [c.credId, { first: unb64(c.prfSalt) }]));
diff --git a/src/renderer/app.js b/src/renderer/app.js
index 0460dd8..2d57532 100644
--- a/src/renderer/app.js
+++ b/src/renderer/app.js
@@ -1338,11 +1338,14 @@ async function importRdm() {
 
 // ============================================================ Updates
 let updateInfo = null;
+let updateDialogOpen = false; // Auto-Prüfung beim Start und manuelle Prüfung sollen keine zwei Dialoge stapeln
 async function showUpdate(info) {
   updateInfo = info;
   const b = $('#updateBadge');
   b.style.display = '';
   b.querySelector('span').textContent = `Update ${info.version}`;
+  if (updateDialogOpen) return;
+  updateDialogOpen = true;
   const r = await modal({
     title: T('MrTerm {v} is available', { v: info.version }),
     text: T('Installed: {v}', { v: info.current }) + (info.asset ? ' · ' + T('Package: {name} ({size})', { name: info.asset.name, size: fmtSize(info.asset.size) }) : ''),
@@ -1350,7 +1353,7 @@ async function showUpdate(info) {
       ${info.kind === 'dev' ? `<p>${T('Development mode: please update via <code>git pull</code>.')}</p>` : !info.asset ? `<p>${T('The release contains no package for this system.')}</p>` : ''}
       <div class="upd-prog" style="display:none"><div class="transfer" style="padding:6px 0"><span class="nm">${T('Downloading …')}</span><span class="pct"></span><div class="bar"><i></i></div></div></div>`,
     buttons: [{ label: T('Later'), value: false, cls: 'ghost' }, { label: T('Release page'), value: 'web', cls: '' }, ...(info.asset && info.kind !== 'dev' ? [{ label: T('Install now'), value: true, cls: 'primary' }] : [])],
-  });
+  }).finally(() => { updateDialogOpen = false; });
   if (r === 'web') return api.call('shell:open', info.url);
   if (r !== true) return;
   toast(T('Downloading update …'));