Marlin's bugfix-2.0.x now contains pin definitions for the Lerdge X and K. I don't own an S, so I have no idea what the pins are. Next steps are to figure out if we HAVE to have a specific board definition (my suspicion is "yes") or if we can build with a generic variant. The reason I think we'd need a specific variant is that the variant's pin config specifices which pins are used by an ADC, and on Lerdge I had issues with the bed pin not having a default ADC definition (I had to uncomment it).