I successfully downgraded my 3GS from 4.0.2 to 4.0.1 earlier this morning but a couple hours later the loud speaker stopped working. They were working fine until I heard a static type noise come out of the speakers. I've tried restoring the phone but that doesn't seem to fix the problem. Whenever I play a song/youtube video/ringtone, I don't hear anything. I've tried plugging in some headsets and I still can't hear anything. The volume is all the way up and it is not on silent mode. Has anyone ever run into this problem? And if so, do you know of a fix?