EDIT: it looks like there is a bug in the Apple TV updater over Ethernet. For obvious bandwidth reasons, my Apple TV is connected to a gigabit switch. #AppleFAIL :(
This morning, I deciced to upgrade my Apple TV 3 to the latest firmware 5.1.1. I left the room and when I returned a few minutes later, the Apple TV screensaver had kicked in. I woke it up to check how the download was doing.
The firmware update window was still blank trying to compute the time remaining. Moving around the menus worked. I guess the firmware download was running in the background since there was a spinning wheel next to the firmware update menu item.
After checking some settings, I returned to the firmware download screen. It was still waiting for the download to start. I was offered to cancel the firmware update. I chosed to cancel since I didn't want to spend all day on this task.
The TV screen turned instantly to black. The remote buttons were acknowledged by a bliking LED but the screen stayed blank. I rebooted the Apple TV and I never saw the Apple logo. My Apple TV was bricked.
I googled "apple tv restore itunes" and ended up on Apple support website "Restoring your Apple TV". I followed the procedure and hooked the Apple TV to my PC. The driver installed. iTunes 11 launched. The Apple TV appeared in the device section. I clicked on the restore button and was greeted with a message box saying that there was no Apple TV connected.
I tried various micro USB cables... even tiny ones connected directly to the back USB ports of the motherboard. Nothing worked. A fragrance of RMA was in the air. Lacking the time to call Apple support, I packed the Apple TV and headed to my parents house for lunch.
Their iTunes was still on the last 10.x version. I connected the Apple TV, it was detected and the restore button worked. I accepted the two warning windows and the firmware download started. It's a huge file for such a limited device... the 622MB firmware took about an hour to download.
Upon completion, the firmware was applied and the Apple TV came back to life.
I know Apple love the "clean interfaces"... IMHO the firmware update page should have the "clean interface" in the back seat. It must show the firmware file size AND the current download speed. I want to know if the firmware file I'm getting is a small delta update or a complete OS image. The user must be able to cancel the update sequence at anytime during the download process without brinking the device.