Useful or not, from you.
Marlin EEprom version mismatch, how to fix?

How is it that we change the eeprom version number?

i did the usual M502 and M500 then M501, but the mismatch in version number is still there

i think its because i tried the a copy of marlin 4 days ago but it has a "bug" that prevents me from controlling a 2nd part cooling fan, so i had to go back to a copy from 5/11 that works

i read that people with radds/due used to flash repetier and then back to marlin to solve it, but that is not an option here, plus the printer is in another room and onboard sd-card of the REARM is hard to get to as wires pass close by, i can do it but i want to limit the amount of walking back and forth and taking the sd card in and out

That's a useful answer
Without any help

Doing a M502 followed by a M500 should resolve any EEPROM version mismatch...

Your mesh data for bed leveling will be preserved. But any other changes to your configuration values will be reset.