Re: Updating controller firmware problem - Marlin

depending on your electronics some are setup so that when you upload new firmware the eeprom is also cleared. (google arduino fuses )

Or you can disable the eeprom features in firmware so its never used.

Or you never used it even when it was enabled, Until eeprom settings are saved for the first time the controller uses the firmware settings, only after first use does the eeprom take precedence over firmware settings