I've rooted my tab one month ago with android 4.2 version. After that an app "Super User" was iinstalled. whenever I installed an app, "Super User" grants approval that app to run.It was all good but unfortunately I tried to update android. And after that my tab struck with "no command" and continuously taking restart. Another problem is "usb debugging" was not enabled, so I can't use usb too. Now friends, plz help me and suggest me how can I use my tab again. Thanks a lot.