If you're encountering problems -- namely an incomplete download or an inability to boot -- when trying to update your Apple TV to version 5.1.1, there's a solution in sight. It turns out that there's a bug with updating the device over Ethernet, so if you've been unable to get 5.1.1 downloaded on a wired connection, disconnect the cable and connect to a WiFi network, then try again. You should be golden.
In the event that an incomplete download of the firmware has left your Apple TV unable to boot, you can connect the device to your computer using a micro-USB cable and do a tethered restore. Just make sure you have iTunes running and you'll see the Apple TV pop up in the devices list. Select it and you'll see the option to restore. Once you've got it back up and running, connect to a WiFi network and perform the system update. You'll be back to streaming in no time.
[Via The Mac Observer]