I have an iPhone 3G on software 3.1.3 jailbroken using Spirit and unlocked using UltraSnow for TMobile. I downloaded TinyUmbrella hoping to save my 3.1.3 shsh but wasn't able to. I was able to somehow save 4.0 shsh. I have the baseband of 5.12.01. If I upgrade to 4.0 using Tiny Umbrella. Will I still be able to jailbreak and unlock it. It's important because I need to be able to use TMobile. Just wondering if this was possible since I've been hearing that if you upgrade your baseband you wont be able to unlock. Thanks.