Finding and exploiting hidden features of Animal Crossing’s NES emulator
Phil Nelson While looking for ways to activate the developer menus left over in Animal Crossing, including the NES emulator game selection menu, I found an interesting feature that exists in the original game that was always active, but never used by Nintendo. In addition to the NES/Famicom games that can be obtained in-game, it was possible to load new NES games from the memory card. I was also able to find a way to exploit this ROM loader to patch custom code and data into the game, allowing for code execution via the memory card.
Incredibly detailed and well-written article, goes super deep into reverse-engineering the technology.