Just a warning, if you get one of these phones network locked, unlock it before upgrading the android.
I have spent a week on this trying to downgrade to 2.1 so I can get to the unlock menu.
I have followed directions from many sites and flashed using kdz, have put recovery on using command prompt, use solution to get the phone to show up menus. Where I fall down is I can not get past the selection where the forums tell me to hold power/camera or other buttons and a menu will come up and give options to select install from sdcard. No matter what I do I can not get to that section??
This is really frustrating me, I have tried so many solution.
However, each time I fail and the phone is black, I just load the recovery with kdz and then click on Android234GT540_06-06-11_eng and this last file auto installs 2.3.4, wonderful, so is there a file like this for 2.1?? if so I pretty sure I can then downgrade then get to the unlock menu.
Or is there another network unlock solution.