Aaaaand just to confuse things, the layout of those settings can change unpredictably from version to version. Newer firmware verifies a version number in the EEPROM and, if the layouts don't match, it will discard the stored values and use compiled-in defaults.insta wrote:Marlin looks in EEPROM for settings
Older versions didn't verify the EEPROM layout, so reloading a much older firmware version will simply misinterpret the newer EEPOM layout as random gibberish and produce exactly the effect you might expect.