My g/f is giving me her old iPhone 3G later as she uses a 3GS. I'm looking to downgrade the firmware because the phone is running really slow. I don't know the name of the current firmware on the 3G but it's the one that added folders and the background picture on the home screen. I figure this is why the phone is running really slowly? If I can downgrade it to before, will I see a significant performance boost? Also, by doing this, will the phone be completely wiped? She said that all the music on the 3G is not on her current laptop and she doesn't want to lose it by me wiping the phone. If this is the solution, how do I go about downgrading it?