Well, that's the minor problem - the main problem is, that since your last 2 changes yesterday it doesn't compile anymore in MAME 0.215!

It already started with a few error messages for your changed mephisto_modular.cpp, but your last total rewrite of mmboard.cpp/h even returned a whole bunch of errors.

If it's not possible to make this Bavaria board work in MAME 0.215, then I'll definitely stop any further work on CB-Emu (or MessChess), because I'm not interested to switch again (the 4th time!) to a new MAME version with all the necessary changes in lots of my sources.

BTW, I saw in your updated *.lay files, that also all those *.lua scripts would have to be changed again (:board:board should be replaced by :board).
And what about all other Mephisto devices (not in mmodular) which also use the mmboard? Would they still work with this changed mmboard driver?

Regards,
Franz