Yes done that, but with baseband of 05.16.05 on newer bootrom you can not install that.Meaning it only unlolocks it for that carrier such as at&t when you jailbreak.Older bootroms with upgraded basebands on 06.15.00,or downgraded basebands on 05.13.04 you can install ultrasnow and it should unlock all carriers.I was having a problem with t-mobile and had to install MobileSubstrate 0.9.3995 to get it working with a older baseband.It was a pain,but I know it should have worked with ultrasnow..So there is a difference between newer and older bootroms what is the difference between unlocking and jailbreaking should be the same.So on the newer bootroms what do you use to unlock,you use ultrasnow for olderbootroms.