As I mentioned a while ago, I had the opportunity to repair a bunch of broken boards for Commodore C16 and Plus/4 computers. This led to a couple of new projects, the ROMulator and the PLA264. To help with the actual repairs, I built myself a Diag264 test harness.
So, I also needed a cartridge to hold the diagnostic ROM. The Diag264 page suggests either modifying an original cartridge or using the OpenC16Cart. Destroying an original cartridge didn’t feel right, so I went with the latter option.