This error occurs when you do not reset your printer EEPROM after updating the firmware. This should be done every time you update the firmware on your machine.
Note: Clearing the EEPROM will reset custom settings that you have entered in. If you have custom settings (example: z offset, steps/mm, acceleration, jerk, etc) these will be back to defaults. Write them down before resetting the EEPROM and enter them in after the reset. Be sure to “Save EEPROM” or send a M500 after entering them to ensure they are stored in the printer EEPROM.
Resetting the EEPROM via EZPi/OctoPrint and Overriding the Error Handling
By default the EZPi/OctoPrint will disconnect from the printer when it detects an error message thrown by your printer. This is problematic when you have a trivial error like the EEPROM datasize one. Here is how you can reset it via the EZPi/Octoprint Terminal once you change a setting in the EZPi/OctoPrint settings to prevent it from disconnecting from the printer when it detects this error. Then we can connect to the printer after we change the EZPi/OctoPrint settings to send an M502 (Clear EEPROM) then M500 (Save EEPROM) to reset and then save the EEPROM reset to the EEPROM.
Follow the images below to change the settings in the EZPi/OctoPrint and then reset your EEPROM.
Note: On the normal OctoPrint Image you will not have the “Clear EEPROM” or “Save EEPROM” buttons. Instead of pressing “Clear EEPROM” type M502 and press enter (this clears the EEPROM). Then instead of pressing “Save EEPROM” type M500 and press enter (this saves the cleared EEPROM settings to the EEPROM).
Resetting the EEPROM via the Printer LCD
You can reset the EEPROM from the Printer LCD by going to Control>Reset EEPROM>Reset EEPROM and then Control>Store Settings. This will clear the EEPROM and then store the default settings.
Note: On regular Marlin printers it will show “Init. EEPROM” instead of “Reset EEPROM”.