https://blog.4dcu.be/diy/2020/10/04/PythonKindleDashboard_2.... ... look just above this link (search for `rtc`) and see some extra stuff here: https://github.com/mattzzw/kindle-clock/blob/master/kindle-c...

other devices may / may-not have RTC clocks or "easy" access to longer-term RTC-style running.