Motorola Droid 2 :: How To Remove ALL Software

[I wish to phrase this so as not to run afoul of the Forum Rules, so please understand that I have no desire to beat my chest or derail the forum with unsupported topics -- I just want an answer]I previously ran a custom ROM on my Droid 2, but for the sake of security and stability I opted to switch back to official Motorola version of Android, which I did carefully and successfully. In the process, I also accepted the OTA update which took my Droid 2 to system version 4.5.621, aka "621".It runs just fine, but yet I'm thoroughly unhappy. According to all the major hacking sites (Rootzwiki, Droidforums, XDA), version 621 cannot be rooted or reverted to a previous OS (due to some kind of 'signature code group'). I've purchased root-only software that I can apparently never run again, plus now I'm missing simple but addictive features like having a music pause button on my lock screen. Having official software has turned out to NOT be worth the tradeoff in features for me, and Motorola gave no warning that the update was locking me in for good.

How do I dump the entire Motorola OS 4.5.621? I'm 100% willing to forego a warranty (which has probably expired anyway), never bother tech support again (this is my first time), and leave this forum forever to go on my merry way with a generic/hacked Android system.