I just purchased a iphone 3gs and a microcell last night and my signal was going crazy with the microcell and I called at&t to trouble shoot, they transferred me to apple where they had me put 4.0.1 on my phone and I really don't care for it. Can someone please tell me how to get 4.0 back on my phone. I have searched and havent really found an answer. Any help would be appreciated. Thanks in advance.