I've tried every port on my computer. I've used every cable I own. I even restored to stock 3.1.3 in linux!! My device simply won't charge or show up in itunes. Not even in recovery mode. I had been running stock 4.0 gm, and I could sync my data after the restore. But after that, it couldn't charge or sync via usb. It CAN in linux, or in an outlet adapter.