Support for custom Sideboard firmware?

[TilCreator]

I found https://github.com/EFeru/hoverboard-sideboard-hack-STM and https://github.com/EFeru/hoverboard-sideboard-hack-GD which provide an alternative firmware for the sideboards.

After noticing that my sideboards were sadly not supported I flashed them with the GD sideboard firmware, but Bipropellant doesn't seam happy with that.
Would it be possible add a "custom sideboard firmware" variant, that would probably also increase the number of compatible sideboards?
From my naive point of view this should be easy as the protocol is open and there is already a similar implementation for the proprietary sideboard protocol, but I could be wrong?