This is a translation of my original article, which was first published on Drive2 Since my Android phone days, I had a cheap ELM327 adapter from AliExpress lying around. I did some reading online beforehand and deliberately picked one with two boards and a PIC18F25K80 controller. The peculiarity of this adapter is …

I have always been into retro devices and hardware projects, and the Game Boy is almost ideal for this: the architecture is relatively simple, and the cartridge interface is well documented. In this article, I will show how I approached reverse-engineering the GB-MAX cartridge and how I implemented minimal read access …