diff --git a/api/setup_manager.py b/api/setup_manager.py
index 788fd28..e7adc23 100644
--- a/api/setup_manager.py
+++ b/api/setup_manager.py
@@ -74,11 +74,22 @@ class SetupManager:
         return bool(self.config_manager.get_identity().get('setup_complete', False))
 
     def get_setup_status(self) -> Dict[str, Any]:
-        """Return current setup status and wizard metadata."""
+        """Return current setup status, wizard metadata, and any pre-configured identity."""
+        identity = self.config_manager.get_identity()
+        preconfigured = {
+            k: v for k, v in {
+                'cell_name':            identity.get('cell_name', ''),
+                'domain_mode':          identity.get('domain_mode', ''),
+                'domain_name':          identity.get('domain_name', ''),
+                'cloudflare_api_token': identity.get('cloudflare_api_token', ''),
+                'duckdns_token':        identity.get('duckdns_token', ''),
+            }.items() if v
+        }
         return {
             'complete': self.is_setup_complete(),
             'available_services': AVAILABLE_SERVICES,
             'available_timezones': AVAILABLE_TIMEZONES,
+            'preconfigured': preconfigured,
         }
 
     # ── validation ────────────────────────────────────────────────────────
diff --git a/scripts/setup_cell.py b/scripts/setup_cell.py
index 9f1ada8..a7d372a 100644
--- a/scripts/setup_cell.py
+++ b/scripts/setup_cell.py
@@ -304,25 +304,28 @@ def register_with_ddns(cell_name: str) -> None:
         print(f'[WARN]    Could not detect public IP: {e} — skipping DDNS registration')
         return
 
-    # Generate TOTP code (requires pyotp; if not available fall back gracefully)
+    # Generate TOTP using stdlib only — no third-party package needed
+    otp = ''
     try:
-        import pyotp
-        otp = pyotp.TOTP(DDNS_TOTP_SECRET).now()
-    except ImportError:
-        # Try python3 -c as a subprocess fallback
-        try:
-            otp = subprocess.check_output(
-                ['python3', '-c', f"import pyotp; print(pyotp.TOTP('{DDNS_TOTP_SECRET}').now())"]
-            ).decode().strip()
-        except Exception as e:
-            print(f'[WARN]    pyotp not available and fallback failed: {e} — skipping DDNS')
-            return
+        import base64 as _b64, hashlib as _hl, hmac as _hmac, struct as _struct
+        import time as _time
+        _key = _b64.b32decode(DDNS_TOTP_SECRET.upper())
+        _t = int(_time.time()) // 30
+        _h = _hmac.new(_key, _struct.pack('>Q', _t), _hl.sha1).digest()
+        _offset = _h[-1] & 0xF
+        _code = _struct.unpack('>I', _h[_offset:_offset + 4])[0] & 0x7FFFFFFF
+        otp = f'{_code % 1_000_000:06d}'
+    except Exception as e:
+        print(f'[WARN]    Could not generate OTP: {e} — registering without OTP header')
 
     data = json.dumps({'name': cell_name, 'ip': public_ip}).encode()
+    headers = {'Content-Type': 'application/json'}
+    if otp:
+        headers['X-Register-OTP'] = otp
     req = urllib.request.Request(
         f'{DDNS_URL}/register',
         data=data,
-        headers={'Content-Type': 'application/json', 'X-Register-OTP': otp},
+        headers=headers,
         method='POST',
     )
     try:
diff --git a/tests/test_setup_manager.py b/tests/test_setup_manager.py
index c21e55e..4d63be3 100644
--- a/tests/test_setup_manager.py
+++ b/tests/test_setup_manager.py
@@ -300,3 +300,23 @@ def test_get_setup_status_timezones_match_module_constant(setup_manager, mock_co
     mock_config_manager.get_identity.return_value = {}
     status = setup_manager.get_setup_status()
     assert status['available_timezones'] == AVAILABLE_TIMEZONES
+
+
+def test_get_setup_status_preconfigured_empty_when_identity_blank(setup_manager, mock_config_manager):
+    mock_config_manager.get_identity.return_value = {}
+    status = setup_manager.get_setup_status()
+    assert status['preconfigured'] == {}
+
+
+def test_get_setup_status_preconfigured_returns_installer_values(setup_manager, mock_config_manager):
+    mock_config_manager.get_identity.return_value = {
+        'cell_name': 'myhome',
+        'domain_mode': 'pic_ngo',
+        'domain_name': 'myhome.pic.ngo',
+    }
+    status = setup_manager.get_setup_status()
+    pre = status['preconfigured']
+    assert pre['cell_name'] == 'myhome'
+    assert pre['domain_mode'] == 'pic_ngo'
+    assert pre['domain_name'] == 'myhome.pic.ngo'
+    assert 'cloudflare_api_token' not in pre
diff --git a/webui/src/pages/Setup.jsx b/webui/src/pages/Setup.jsx
index f3d792d..a6bbdda 100644
--- a/webui/src/pages/Setup.jsx
+++ b/webui/src/pages/Setup.jsx
@@ -1,4 +1,4 @@
-import React, { useState, useMemo } from 'react';
+import React, { useState, useMemo, useEffect } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { Eye, EyeOff, CheckCircle, AlertCircle, Globe } from 'lucide-react';
 import { setupAPI } from '../services/api';
@@ -789,6 +789,25 @@ export default function Setup() {
   const [submitting, setSubmitting] = useState(false);
   const [submitError, setSubmitError] = useState('');
 
+  // Pre-fill from installer config if present
+  useEffect(() => {
+    setupAPI.getStatus()
+      .then(res => {
+        const pre = res.data?.preconfigured;
+        if (!pre) return;
+        if (pre.cell_name)  setCellName(pre.cell_name);
+        if (pre.domain_mode) {
+          if      (pre.domain_mode === 'pic_ngo') setDomainType('pic_ngo');
+          else if (pre.domain_mode === 'lan')     setDomainType('lan');
+          else { setDomainType('custom'); setCustomMethod(pre.domain_mode); }
+        }
+        if (pre.domain_name)          setCustomDomain(pre.domain_name);
+        if (pre.cloudflare_api_token) setCloudflareToken(pre.cloudflare_api_token);
+        if (pre.duckdns_token)        setDuckdnsToken(pre.duckdns_token);
+      })
+      .catch(() => {}); // fail silently — wizard works from scratch
+  }, []);
+
   const skipStep4 = domainType === 'lan';
 
   const goNext = () => setStep(s => Math.min(s + 1, TOTAL_STEPS));