I've also experienced the same lockups with b7 & b11. I too have turned the ignition off whilst a lockup is in progress and the player remains on and the amps also remain on. First time this happened was filling up with petrol so didn't reboot, left music playing for passengers, when the ignition was turned back on the player switched into standby, and had to be pulled to reboot. The lockups allways occur with the hard disc spin up icon activated but without the central disc read portion lit.

Mark.