Hi, first time poster long time lurker! Anyways, was wondering if you guys/gals could help, or at least guide me with some questions. I want to sell my 2G iPhone to my friend, but the problem is he is on t mobile (U.S). I know you can unlock it and put it on any GSM carrier, but I have 2.1.1 and I don't know how to downgrade it to an unlockable version, if at all possible(I am using Windows BTW). I know how to go about unlocking once the iPhone is using a hackable version, but I dont know how to downgrade firmware. I used the search engine and searched google, but could not find any thing specifcally about downgrading 2.1.1. So my question is how do you downgrade your firmware and also how can I "wipe" the phone before resale? Any and all help would be greatly appreciated!