Going back to a previous ATV version (like 2.1)

Does anybody know if there is a way to rollback to a previous version of the ATV firmware? Some of the hacks seem to be having a few compatibility problems with Version 2.3. I would like to take my ATV back to 2.1 from 2.3 or to do a reset and update from 2.02 to 2.1.

Is there a simple way of doing this? Can I use the “Smart Installer” by uploading 2Z694-5485-1.dmg (found at http://mesu.apple.com/data/OS/061-5044.20080709.de43E/2Z694-5485-1.dmg) into the Documents directory? I have tried to do some research on this but have not had much luck. If anyone has any suggestions or directions it would be greatly appreciated.