I accidentally got the center screen blacked out and could not wake it up.
But since I was playing with USB music sticks, I did the Computer Repair 101: Shut car off, unplug USB devices, turn car back on. Voila!
I have a computer that won't boot when an i-Phone is plugged into a USB. This car might have the same habit.
Just an idea to try before visiting the dealer. Unplug everything you can with the car off, then try to boot it again.
Sidenote: When the dash display NAV won't come up: When you start your car, push the NAV bar on the center console Home page. You will see it twirling colored squares. Just wait. When the NAV finally comes up fully, your Dash NAV image will too.