Just got my at Iphone 3Gs It has firmware 3.0.1 and modem 04.26.08. It was already unlocked using Ultrasn0w (Cydia). First, should I upgrade to 3.1.2 or just leave it alone? If I do the upgrade, how do I keep the 04.26.08 modem firmware? I've read a lot but still a bit confused. Thanks.