I've tried to search, but the posts I see all seem to be aimed at jailbreakers. My iPhone 3G isn't jailbroken, and I'm not planning on doing so. But, the 3G has become quite sluggish since I update it to iOS4, and I would like to return it to the last version. Can some kind soul point me to the right place to learn how to do this? I have only upgraded to new versions in the past, never tried to go back. I'm not sure Apple did me a favor by allowing iOS4 on the 3G.