Okay so here is the situation. I am out of my home country and my only working contact to the outside world is through my iPod touch. All is going well with this method, when all of a sudden, sound stops working on my iPod. Music, when played, instantly switches to pause. I researched this problem and found that the only fix is to upgrade or downgrade firmware. So I've decided now is a good time to just make the jump to 4.0. I'm currently running 3.1.2 and jailbroken with blackrain. I have very limited access to a friends computer, so if I just plug my iPod in and upgrade to 4.0, will it just remove my jailbreak? I am aware a lot of extra data will be left on my iPod but I can fix that when I get home. For now I just need to be able to listen to music on the flight home. Will my plan work or am I SOL?