I think the suggestion is just before reboot, you could use poke() to save the current time somewhere safe, and then use peek() to get it later.
If there is really an offset between the OS clock and RTC time after reboot, maybe calling the time setting eventprocs to the current time would update it.
Thanks, i'll dive into srsa_4c suggestion and your script.
If you look at the csv, you see the log entrys have earlyer timings after reboot, so yes there really is an offset.
If canon os clock runs quicker than the RTC time on the battery and at boot it checks RTC time.
Storing at shutdown and loading stored time at boot would result in the same problem minus 10-15 sec.
So my first thought would be to use the reboot timestamp, should give a 10-15sec correction on canon os clock every time it reboots.
Not enough for my taste, but this way there are no conflicting times and it's already available when the script calls for a reboot.
Now implementing that idea.....
there is only one thing that's bothering me in this assumption.
if there is a difference between os and rtc after a while why haven't i encountered that when switching an sd card within 30 seconds, if it then initialises the rtc time it should also have had an earlyer timestamp on the new run, but those have a correct downtime gap.