[kragen]

i thought about that but you also have to port the apps, many of which use self-modifying code, which flash program memory is not enthusiastic about

[bpye]

Someone on the blog post linked suggested implementing the BIOS calls in AVR code with some sort of mode switch, I guess you could go further. Port CP/M keeping syscall compatibility but use a CPU emulator for application code.

[kragen]

sounds sensible