Nexus 10 - Android 5.0.1 OTA upgrade, “no command” and suggested steps failed

I did rooting with Kingo root, and also i did factory reset. but i still can't use OTG When I press power+voldown, boot menu starts and immediately shows "Downloading... Do not turn of target!" then i tried Hold Power + Volume Up + Volume Down, and then i can see recovery mode, but it still not working - no command ... I still see "System update download" , still failed. what can i try more?