Updating a jailbroken ATV2 to iOS 5

I recently updated my ATV2 to iOS 5 (w/ tethered jailbreak, - tethered meaning you need to connect the ATV2 to your computer each time to re-power or else the ATV2 won't boot-up).  Updating is easy as cheese if it's not jailbroken, but since mine was the experience definitely brings to mind the saying "if it works, don't touch it".  The good news it that it eventually worked!

So why did I touch it?  I learned about the new AirPlay feature on the iPhone 4s, after a visit to the Apple store, and wanted to try this out.  Unfortunately, my jailbroken ATV2 was stuck at iOS 4, which doesn't support this new feature.

So here's how it went:

First I followed this video: http://www.youtube.com/watch?v=dX1bsSL9bUw, which I found on the wiki.xbmc.org site.  Unfortunately, each attempt to use SeasOnPass to re-jailbreak the ATV2 resulted in an error from iTunes (error 21) and the jailbreak ultimately failing, leaving the ATV2 in a useless state.

Google searches for the error 21 come up with suggestions like: try a different cable, try again (and again, and again), restart computer, first make sure a standard restore works from iTunes.

Unfortunately a standard restore through iTunes always resulted in the same error.  And no luck with several re-tries or restarts.  Great, did I brick my ATV2?  With each re-try I have to restart SeasOnPass, which for some reason takes 5+ minutes to load, so I gave up for now...

Well, as it turns out, re-try (again and again) was the answer.  Came back a week later and tried again (may have used a different USB port) and it worked the first try when using SeasOnPass.

From here on, things went relatively smoothly.  Here are the basics steps after getting SeasOnPass loaded.

1. Used the NitoTV installer downloaded from here: http://i0sen.dyndns.org/jailbreak-Tools.html
2. Under ATV2 settings, set sleep to NEVER.
3.  Followed instruction at XBMC to install latest unofficial Eden version for iOS 5 as given in this post: http://forum.xbmc.org/showthread.php?tid=127369
4. Re-load backed-up XBMC folder (assuming you followed the YouTube instructions)

 I haven't actually tried step 4 yet, but I'll find out soon how it goes.

Hope this helps somebody.