After adding some pullups to the L pins, I have what looks like a good and proper COP411 dump now. Disassembly shows what looks like proper code, setting up RAM and ports and then getting stuck at a loop on the port pin that connects to the other CPU.

Then code after that is reading the L port to get the command from the CPU and it pings it to say it received it and then it does god knows what to generate the audio. the end!

Tonight's goal is to dump the ms pac CPU (easy/fast) and then play around a bit with the M58846 mitsubishi chip from frogger.