I discovered that my F920BT worked perfectly and didn't restart (reboot) when I started the car. 

It never had updated the firmware, but today I updated the firmware to the latest version (2.00300) published by Pioneer.

My surprise was that after the firmware update my AVIC F520BT restarts (reboot) when I turn on my car.

How can I do a downgrade to know if the error is the firmware ????

Has someone had the same error ????

Thanks.