[zokier]

You are right, the situation is better that what I thought, the commercial smbstax SDK might not be absolutely required.

They even have some BSP stuff freely available which is really positive sign. https://github.com/microchip-ung/bsp-doc

This would be such an enticing project to jump into, there are just enough bits to make it seem doable, even if the realist in me knows its not really feasible.