I think the boot sequence is too long, particularly when you starting the engine and immediately need the reverse camera.
I have a big capacitor and a diode on the red ACC wire. When i turn off the ACC the F900BT stays on for 10 sec. Then I have time to turn it back on if I erroneous turn the key to far to the left.
But the capacitor is not enough to hold the system up and running during engine start (on my 2009 Hyundai Santa Fe anyway). This I solved by a little gel battery and a 1 way diode on the +12V always on wire. It works nice.
