Hi resident Hackint0sh experts,
I have a jailbroken / unlocked iphone 2G running v2.2.1. I used quickpwn to get to this stage. My phone is currently on the T-mobile network.
Can anyone lay out (or point me to) a step-by-step guide on how to go about upgrading to v3.1.2 using Windows. Should I use pwnagetool, etc, etc. Finally, at the moment I have no issues with SMS, email, wifi, push, or anything else for that matter. Will the upgrade to 3.1.2 affect any of these functions?
The help would be much appreciated.

P.S. Unless I am mistaken, any reply that is sufficiently detailed should be posted as a sticky for future use by many other people who appear to have the same question.