I've been working on the missing background emulation in Irem's Beyond Kung-Fu.
I now have a functional implementation that reconstructs the stage backgrounds at runtime from the original km-z.4h ROM data.
The current result has been extensively compared against original PCB footage, including background geometry, scrolling, dynamic elements, clear/restore behavior and sprite/background priority.
Current MAME build:
https://www.youtube.com/watch?v=CJkNmFXWFzc
This does not claim recovery of the original MCU firmware or its exact historical implementation.
I am still finishing a few small adjustments. Once complete, what would be the preferred way to submit the work for possible inclusion in MAME?