[cctalk] vt220 firmware source?

Hi folks, I’m working on a vt220 debug/repair and have gotten to the point where I need to trace firmware execution at boot. I’ve managed to dump the proms (close to but slightly different from the versions in Lars’ GitHub) and the 8051 internal rom, and can load and disassemble these with the s51 simulator. I also have an HP 1660 logic analyzer successfully configured and clipped up to capture instruction traces. I’m about to dive in to commenting the disassembly listings, but figured I’d ping here to see if anybody might have done this already in case I wouldn’t have to start from scratch? thanks much, —FritzM.