I’ve added a 16KB RAM expansion to the MiST port of the Apple II+. It’s seen as a language card in slot 0.
I’m also working on a Saturn 128KB RAM expansion but it’s not working yet and need some more work.
To implement both I made use of some manuals available on the net which show the control codes for those cards which need to be implemented in the hardware.
See: LANGCARDMAN.pdf Appendix D page 25
and: Saturn Systems 64K and 128K RAM Board – Operations Manual.pdf Chapter 9 page 68
Binaries are now on the MiST github repository: https://github.com/mist-devel/mist-binaries