[Android Head-Units] kaween:
Hello. Thank you for chiming in on this one, I do appriciate it very much.

I tested the unit without anything hooked to the USB or even the internal memory card reader just to be sure. The whole radio circuit, the actual speaker and subwoofer circuit is grounded with several redundant gound lines, and at each point, the resistance between car body, battery ground and sound system is 0 Ohm. (oh yes, ZERO. Well, 0,2 actually after recallibrating my ancient high precission 50 year old Hansen Analogue Multi Meter for the resistance loss of it measurement leads. :) I did my homework on this install)

I've been attempting to debug the situation for the greater part of the day, and I think I've found the reason, and it confirms my suspicion that the reason is to be found in the power-part of my AN21. Your info only seems to confirm I'm not the only one with a somewhat dodgy AN21 power circuit.

Please join me in a mind experiment here :

1) I've tested this unit outside of my car for weeks prior to building it into my car. I've never seen this issue prior to building it into the car. Of course, I've never done a power off/power down just for the fun of it, so I do not know if it would have happened if I'd done that kind of test. Note : the testbench I used puts out 13.5V to simulate the voltage of a normal car with running engine/alternator.

2) In my car, the voltage is typically 12,3V, but after a couple of short distance trips and parking the car, that voltage will drop to 12V or lower. So most of the times, I'd be doing the tests in the car with voltages WELL below the 13.X Vdc I have on my testbench. And of course, with each attempt, the voltage would be slightly LOWER than the previous attempt. So maybe the whole "you need to wait X-seconds for a succesful repower" could be the time the BATTERY needed to recover back to an acceptable voltage level ?!

3) I didn't take this in account when I tried the unit outside the car after noticing this "death white" issue, I simply took a precharged 12V battery and hooked my testrig to it, only to see the problem was present too this time outside of the car.

4) Today, I realised the tests in "3" where different as I did not use the same power supply, and thus the test was invalid. So I took a shortcut : I reinstalled my pico-ups which I had removed from the car to exclude it as reason for the issue, and precharged its backup battery to full charge and KEPT it charging, thus creating a voltage leel that would be above 13V at all times. And lo-and-behold, after 100 reboots I still hadn't seen the white screen.

I'll be testing this for the week to come, but so far this seems a logical explenation for this odd case.

Anyhow, I'm now on the lookout for a MCU version 4.2.5-1-10-6101 . I did receive an alternative version from the friendly user droc.noles, but it didn't really do the trick.

QUESTION. Is it possible the result of a bad MCU can be rectified by a FULL factory reload ? I mean, is it possible that, using an old, unappropriate mcu, the results are written into the system which can not be rectified by the "correct" mcu unless ALL settings are reset to default ? (which does NOT happen with a normal reflash or reset, there's no doubt about that as even reflashing the unit with a new firmware simply retains info like button info, swc info, radio tuner stations and the whole crapload of other info ...)