My F90BT is doing the same thing. 1 in about 60 tries, it will work. I use the term "work" loosely, as the navigation appears to be stuck on a spot that I have not been in for 3 days. Otherwise it will reboot, show booting for 8 to 12 seconds, go blank for 2 seconds, then reboot again. Pioneer SERIOUSLY needs to start noting these problems. This is annoying as hell, and I can't seem to find a fix.
I miss my D3. Never should have bought this stupid piece of $h!7.