I'm having some strange issues with my USB drive as well... I've got a High Speed 8gb thumb drive. For some reason it randomly has to "index". This doesn't happen every time I turn the car on but enough to be annoying.
The second issue I have is that the screen goes blank and all it shows is the USB icon. The song still plays and you can advance to the next one. Even the menu is blank. FM/XM is normal, but the only way to get the screen back for USB is to shut the car off for an extended amount of time.
And the fact that it doesn't stay on random when you turn your car back on is annoying too. I was hoping for a little more from the USB.
2SS/RS LS3 CGM/Black
1000, Dealer Order (4.06.09)
1100, Preliminary order accepted (04.09.09)
2000, Order accepted by GM (4.16.09)
3000, Order accepted by production control (4.21.09)
3100, Order available to sequence (5.14.09)
3300, Order scheduled for production (5.14.09)
3400, Order broadcast (5.21.09)
3800, Order produced (5.29.09)
4000, Available to ship (5.29.09)
4200, Shipped (5.29.09)
4800, Rail Ramp Unload (5.30.09)
5000, Delivered to the dealer (6.10.09)
6000, Delivered to the customer (6.11.09)