Probably your best bet would be to use the LG Updater Tool and let it upgrade your Optimus M to Android 2.2.2. If you haven't used it before, you should be able to use it (from what I've read and seen, it's a one shot thing, meaning that if you do the upgrade and then root it and put on a custom rom, it won't let you "upgrade" again, it'll tell you you already have the latest version). This'll put your phone back to completely stock. I performed it on my phone once, and it worked well. My phone started life as Android 2.2, I rooted and put on various 2.2, and 2.2.1 ROM's and then finally put on the 2.3.x CM7 ROM's (tried all three and stayed on reppards). When the root method came out for 2.2.2, I decided to give it a try, just for kicks, and so upgraded my phone using the LG Updater tool. Once it was upgraded, I proceeded to root it. After it was rooted, I left it for a little bit, then put on the Kelso 2.2.2 ROM. Finally I went back to reppards CM7 ROM. Anyway, sorry for the ramble. My suggestion is to try the LG tool.