It says right there when you downloaded that you have to be on .588 before you flash .591. I've never done it because until now just too complicated. That's why I went GBLib. One file. He's supposed to come out with something tomorrow so maybe wait to see what it is but here's what I would do if I were you. 1. Back up apps with Titanium. 2. Export contacts to sd card. 3. Boot into recovery using D2. (Some still use DX but you have to go to settings, applications, development and uncheck USB debugging). 4. Make a backup of your 2.2.1 5. Wipe data/factory (I always go to mounts and storage, format data and then format cache. It's the same as wiping but either way is fine. 6. Install the update.zip (.588 rooted) from TBH app. One file instead of three. 7. Reboot (should boot once into .588 just to make sure you made it that far.) Google may try to restore your apps. If so, wait or stop the dl's. 8. Get D2 from market and start process over beginning at step 3 and when you get to step 4, backup .588. Don't forget step 5 (wipe data/factory or mounts and storage, format data, format cache.) 9. Repeat step 6 but this time you're installing .591, rooted, deodexed. 10. Reboot 11. Get Titanium from market and restore apps and data. Google may try to do it again. 12. Contacts should be there, if not, import from sd card. 13. Reboot. If everything goes according to plan you've got what you wanted. Latest GB (hopefully final GB), Rooted and deodexed. Again, this is what I would do. If you want to hold out and get help from someone that's done it, fine if that makes you comfortable. Either way you've got to pull the trigger sometime. Good luck.