I just pushed a BigBox Dual firmware based on the RCBugFix branch of Marlin to my Github Marlin repo: https://github.com/Alex9779/Marlin/tree/BigBox_Dual Check the PID settings either before you compile of after, I set it to values I got from my second extruder. Same applies to bed PID. Still didn't check if I need to set different values of PID for the hotends so that option is still deactivated... Think I am going to test that today. Did some minor changes to the config and activated the filament and baby stepping option.