I should stick to the one I do.

Preferred method
Using a terminal that can send G-Code.
M502 reverts to the default "factory settings". You still need to store them in EEPROM
M500 stores parameters in EEPROM

Another Way.
Using the LCD with Marlin loaded
Restore Fail-safe, Load Defaults then Store Memory

Any changes made then stored will then be the system defaults after reboot.