Now I'm not sure if this will work without SBF, but you can try installing the 2-part rooted GB followed by LGB 0.x, then doing a data wipe, and see if that does it for you. Personally I'd SBF. Instructions for that process (as well as links to the files you need in any case) are posted here:
If you are going back to Liberty 2.0.1 you can simply wipe data/cache and davlik and flash it. You do not need to sbf to go to 2.0.1, but follow the above instructions if you are thinking of going to Liberty GB. I recently flashed 2.0.1 over CM7 and am so happy to be back on Liberty. I cannot deal with the battery drain on CM7. Good Luck!