I would prefer too to stay with this firmware.
Maybe developers are reading this too and will consider adding some option to power down device using a SSH command.
That way I could try something like Tasker (android) to sent such command.
Something like:
IF phone disconnects from Car Radio (Bluetooth trigger)
THEN SSH [power_down] command
to 192.168.8.1
When car is started (or carkey turned) again, the router will start charging and as a result start booting.
I read somewhere that auto booting when charging is not what some people like so that is considered to be optional in feature firmware release.
But: This kind of IFTTT solution can be a difficult job when there are more users (like my girlfriend using the car too, or worse, driving together and one leaving the car)