Octoprint & EEPROM CRC checksum Errors

If you get an error in Octoprint (1.3.6) after uploading firmware (1.1.8) after enabling the EEPROM feature in Marlin, its not a problem per say, its a feature. Octoprint may complain about CRC checksum errors and will not allow you to connect. This is normal...

I am posting this here because I can not figure out where else to report the info. If you try searching for the issue, you will end up on wild goose chase that leads to nowhere.

The EEPROM is disabled be default in Marlin config file. Explanation here: [github.com]

If you want to use something like the EEPROM editor plugin in Octoprint, you need to enable the EEPROM feature. Problem is, once you load the new firmware to the printer, Octoprint may report a CRC checksum error and refuse to connect to the printer. This is because Octoprint is setup to halt on EEPROM errors.

In order to clear the mismatch of the checksums, you have to temporarily disable the feature in Octoprint.

1. Go to Octoprint settings and look towards the middle/ bottom of the page, for a checkbox that is labeled "Ignore and unhandled errors from the firmware..."

Check that box.

2. Restart Octoprint either through the navbar power button or via an ssh terminal " sudo service octoprint stop"

3. Reset/reboot your printer.

4. When the printer has finished rebooting, Connect with Octoprint. It may take a moment, but that is to be expected.

5. In the Terminal, issue a M502 command to factory reset the firmware to clear out any lingering data.

6. In the Terminal, issue a M500 command to factory reset the firmware to reset the EEPROM.

7. Verify by issuing an M503 command to report the settings stored in the EEPROM.

8. If you wish, test the EEPROM editor plugin.

9. Once satisfied that this worked, re-enable the Octoprint setting by unchecking the box you checked in step one.

Hopefully, this message in a bottle will find its way to the next poor soul who needs it instead of them wasting time reading posts by well meaning people who don't know squat about bumpkiss..

Thank You !!!

I had this issue now almost a year later (for some reason this only happened for me when I added another extruder).
This solution works perfectly!

Also, to make the first step easier for new users, the setting is located in "Settings -> Serial Connection -> Behavior -> Error Handling -> What to do on firmware error".