I have an iPhone 3G that I upgraded to iOS 4. Since the upgrade, almost every call has been dropped. Prior to the upgrade, dropped calls were rare for me. I did have a lot of trouble with the upgrade, and eventually had to do a restore to finally get it done. I am a heavy user, though, and these constant dropped cals are killing me. Any ideas on what I can do - settings changed, reinstall, anything? Thank you.