or unlock on tmobile? I have an iphone 3G that is unlocked and jailbroken (used blackra!n) over a year ago. I want to upgrade the os, as many apps won't run on the os3.1.2. How can I upgrade without losing my cydia apps or the ability to have an unlocked and jailbroken phone on Tmobile. Also, I don't want to upgrade to an os that will make my 16gb iphone 3g run slower than it already is- pretty slow.