The OpenCube is a CubeX Duo that I converted to opensource by replacing the hardware with opensource componants. I plan on making a blog and video about the conversion in the near future but I thought it would be a good idea to share the firmware I customized to work on the Rambo board that is in installed in the printer.
I interfaced the Rambo board with all of the stock hardware with the exception of the Z endstop for which I used an optical trigger. I have collected the parts to add a heated bed to the printer but I have decided to just leave it as is and use it for PLA.
You can find the firmware here.
*Disclaimer* I make no claims to the quality and function of this firmware as there are multiple ways to setup your 3D Printer. Use at your own risk.*
It may be a good idea to just look at what I have done with the settings in my firmware and see if you can apply it to your own customized firmware.