the list of things to investigate is growing faster than I can dig through it! 

Host Software

Until now the interface to the AVR has been a text interface. This was great for initial debugging but it gets tedious to have to paste hex into a console, and isn’t great for machine control. I’ve designed a rough binary protocol for this, and I’ve started writing a library and GUI utility to implement it. The idea is the library can also be built into command line tools for uploads

Debugging

Speaking of testing and debugging, the memory programming seems to be a little broken. Not sure what happened there but I need to figure it out at some point.

C Maybe?

I stumbled upon z88dk and it looks like it might be quite useful as a way to make C programming for the platform easier, while still allowing calling precanned rom utilities.

Hmm many things to look into!