Recent update locked up AppleTV. It started the update, then locked up and the light began flashing slowly. This went on for days, even though I unplugged and restarted it several times. Then, when I tried to restore in iTunes, the AppleTV started flashing very quickly. iTunes said it could not find the device even though it appeared in the device list. How do I complete the update and get this thing working again.
Apple TV (3rd generation), OS X Mountain Lion (10.8.2)