hope this message finds you all in time. The recent Apple TV update 5.1 is terrible. Apple knows it is which is why (thankfully for some relentless user -I have no idea who but I believe it was under threat) they have allowed to sign 5.0.2 again which means you can downgrade your Apple TV 2 and 3 to a 5.0.2 version via iTunes. Who knows how long they will keep the window open but I have downgraded my ATV early this morning. I couldn't post this earlier because I was out all day but I am doing it now.
Here's how to do it:
1) Connect your ATV to your computer via a Mini USB (not included with ATV but included with many other electronic devices) - in order for your ATV to appear in iTunes you must FIRST plug the USB cable to your computer and ATV and only THEN plug the power cable.
2) Download your ipsw restore file from Apple.
5.0.2 (ATV 2): AppleTV2,1_5.0.2_9B830_Restore.ipsw
5.0.2 (ATV 3): AppleTV3,1_5.0.2_9B830_Restore.ipsw
3) In iTunes select yout ATV, hold SHIFT and click on Restore
4) Find and choose the downloaded IPSW file in the Open Dialog Box and hit Next
5) As long as Apple still signs that version the Restore process will begin and will take a few minutes to complete.