MR = maintainance release.
If someone can save and post the original Recovery Upgrade Utility (RUU) then you would be able to roll back if and when it's needed. The RUU would be like an OTA reinstall of the OS, and something you should be able to get from VZW. It's a windows program that lets you plug in the phone, click one icon, and restore a bricked droid.
I've been trying to get a copy of it, but the VZW stores I do work for claim that only a subscriber can get it, which I'm not. I will keep trying though
I'm trying the line "How can I repair phones without the required software?"...but getting the response "You don't need it to replace batteries. You just want it to mess with." Can hardly argue with their logic lol.