PLEASE HELP --- 3G update
I'm sorry if this is not the right forum to post this (admins feel free to move the thread somewhere else if appropriate).
I have an iPhone 3G running on iOS 3.0. Baseband is 04.26.08 and Bootloader is 6.2 (info from f0recast).
It is jailbroken, and unlocked with ultrasn0w. I got the phone like that from a friend, I didn't jailbreak it myself.
I want to update the OS to a newer versions (the latest possible, actually), but I'm not sure how to do it without losing the jailbreak and unlock.
I've been asking around and the first thing I was told to do is save the SHSH in Cydia's servers (Cydia reports SHSH saved for 4.0, 4.0.1 and 4.0.2, but I'm positive I have iOS 3.0; Cydia itself reports iOS 3.0 at the bottom), for which apparently I have to update the OS first to 3.1.2 using Restore from iTunes. (I have already downloaded 3.1.2 from Apple just in case, but I haven't used it). However, I don't know what happens after I update, I'm not sure how to jailbreak and unlock again.
And once I do that, how do I update again to keep the jailbreak and the unlock?
Sorry if this sounds too stupid, but I'm really afraid I will lose the phone if I do something wrong.
If someone could explain to me in detail what steps I should follow, I will be very grateful.