Possible fix for update issues:
The update process is imperfect for major updates on all Android, leading to any number of odd problems.
Many find these problems go away with a factory reset.
In this first link below, I think I explain this (better than I did previously) what the cause of random problems are, where some suffer, some do not. It links from there to the Evo thread that gives as many strategies as possible to save and restore your stuff so you lose little to none from the reset. The Evo thread was proctored by me, but was a community/team effort to get this squared away for us Evo users.
Since then, this advice has traveled far and wide on our forums with many positive results - so it's not just an Evo thing or HTC thing or even a Froyo thing.
The worst thing that happens for you following our steps is that you get a good backup strategy in case the reset doesn't work and you get your replaced - not too shabby.
You have to work around the Sprint-specific stuff, but I imagine you cats will see through that quickly.
Sorry the instructions for backup are long - they're accommodating rooted and regular users and those who can afford to pay for backup apps as well as those that cannot. Just scan first, then read, so you'll see it a clear procedure with branching for your particular case - then it won't seem so long to read and adopt.
The Facebook links are out of date - sorry, consult this forum for any FB info for the Bolt.
Ignore the warning to avoid if not your phone - that was actually for Droid X users whose phones would brick until that all got resolved.
This is really a staff favorite, guides, mods and even admin, so that's your recommendation right there.
Really hope this clarifies why to do this, and then helps.
http://androidforums.com/fascinate-support-troubleshooting/323542-how-fix-froyo.html
BTW - rooters actually do this often from their bootloaders or ROM Manager when swapping roms sometimes - this way is way more better (I meant to do that).
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Conventional wisdom - if you're rooted, never accept an OTA update. You should be able turn that off in your settings under Updates. Look for your updated rooted stock rom at XDA.
Your Thunderbolt rom and kernel master listing is here:
The Official Thunderbolt ROMs and Kernels Listing (Updated 5/12/11 1:40 PM CST) - xda-developers
Hope this helps, even if only a little!