Hello iPhone wizards, I'm sorry to be another newbie here and post something that's likely already been discussed. I know there are a billion threads out there on this topic, but I can't seem to sort through it all and get a straight enough (and recent) answer to figure out what we're getting into here. I have a 16GB 3GS I jailbroke for a friend using PwnageTool 4.2. This kept the Baseband as 05.15.04. From what I understand, in order to unlock it now (my friend has T-mobile), we need to upgrade the baseband to 06.15.00 using ultrasn0w, right? I tried to unlock it with the 05.15.04 baseband but it says "Searching..." and never connects to the network when we put the T-mobile SIM in the phone. I assume this means it's not unlocked and I did it wrong. Will upgrading to 06.15.00 kill the GPS? Is there any way of getting it back if it does kill GPS? Is there any other functionality that will be lost if we do this? Should I use another jail breaking program? I read a suggestion about Greenpois0n but I don't see how that correlates with unlocking/upgrading the baseband... I might be missing something here. What Would MacRumors Do?? Again, sorry to clutter the boards, but just looking for a straight forward answer for my particular situation. Thanks!