Try the mobile interface link in site

applications/admin/views/default.mobile/index.html

@@ -11,6 +11,7 @@
       <tr><td>{{=T('Administrator Password:')}}</td><td><input type="password" name="password" id="password"/></td></tr>
       <tr><td></td><td><button name="login">{{=T('Login')}}</button></td></tr>
     </table>
+    <input type="hidden" name="is_mobile" value="true"/>
   </form>
 </div>
 {{else:}}