I've been in contact with Steve Hunt, who dumped the m3 ROMs and wrote the replacement monitor ROM. He gave me his custom CP/M floppy images, so that I've been able to hook up floppy support:
![[Linked Image from i.imgur.com]](https://i.imgur.com/0n8gKCP.png)
![[Linked Image from i.imgur.com]](https://i.imgur.com/4FeV6JU.png)
Still no official software, but at least the machine is usable now.
I also have a new version of the monitor ROM that supports booting from IDE.