You could also write something like Linux's fakehwclock that writes device time to a file on shutdown and reads it on bootup. Your clock will skew more (shutdow

You could also write something like Linux's fakehwclock that writes device time to a file on shutdown and reads it on bootup. Your clock will skew more (shutdowns are supposedly 0 seconds in duration), but it would at least be monotonic. Fakehwclock is cool for computers with no clock battery like raspberry pis. So you at least have a time from this century until clock sync