Need to give you more background. It began with a suddenly ultra low brightness. I was still able to see something, tried to increase brightness but nothing happened. Faced this approx 3 to 4 times in the last half year. Was already A13. Usually it helped to remove the batterie and start the phone again. So no did not happened right after an update.
Before I flashed again yes, example: Sitting in the car, phone was black and connected to carbluetooth.
Yes that could be very likely.
I read this advice more than once, but unfortunately I don’t have the fitting equipment. Will see if I can test it that way.