I was playing around with a new Ender 3 Pro at the maker space and noticed the Change Filament option was gone. This option was useful because it would eject filament instead of having to pull it out by hand when you wanted to change it. Our other Ender 3 Pro has a mini USB plug, but this one has a micro USB plug.

That got me into researching the new 32-bit boards for this printer and how they disabled the Change Filament feature. I learned about the Marlin firmware, Marlin Auto Build, and its custom configurations. It’s a bit complicated, but this Youtube video helped a lot by walking through the process. I used bugfix-2.1.x branch, copied the contents of Configurations\config\examples\Creality\Ender-3 Pro\CrealityV427
configuration to the Marlin directory, built the firmware, copied it to a SD card, and installed it, but the Change Filament option still wasn’t there! I found this post explaining that the ADVANCED_PAUSE_FEATURE and NOZZLE_PARK_FEATURE had to be enabled. The first feature was enabled, but I had to uncomment the second one in Configurations.h.

I rebuilt the firmware and Change Filament is still not showing up. Guess I’ll have to keep looking into this…