The Super NES CD-ROM famously never happened — Nintendo and Sony fell out, Sony walked away and eventually turned the leftover engineering into the PlayStation. The NES, one generation earlier, never got anywhere near that close to an optical add-on. Hobbyist developer Throaty Mumbo decided that gap in console history was worth closing anyway, building NESCD, a real, working CD drive expansion for the original 1983 Nintendo Entertainment System.
Reading a disc a 40-year-old console was never built to see
The NES has no concept of optical media, so NESCD does its work entirely outside the console’s own logic. A custom PCB built around an RP2350B microcontroller sits between a standard 40-pin IDE CD drive and a Krikzz Everdrive N8 Pro flash cartridge — the same widely-used NES flash cart hobbyists already rely on for running homebrew and backups. The RP2350B reads a game’s ROM data directly off the disc, then streams it over USB into the Everdrive cartridge, which the NES then boots and runs exactly as if the game had shipped on a normal cartridge in the first place. A PCM5102 DAC handles audio output, piped through the console’s expansion port, and a single Molex connector supplies power to both the CD drive and the bridge board, with an option to route power back out to the NES itself.
Beyond simple ROM loading, Mumbo’s board also does full-motion-video streaming, decoded through custom bitstream code running on a Cyclone IV FPGA — the harder, more interesting half of the project, since NES-era hardware has nothing resembling native video playback to lean on.
A thought experiment, not a product
By Mumbo’s own framing, NESCD is deliberately a “what if” — an answer to the question of what the NES generation might have looked like with the CD-ROM add-on the SNES generation never got. It’s not aimed at being a practical way to play games; it’s a demonstration of what 1980s console hardware becomes when a modern microcontroller does the heavy lifting a period-accurate chipset never could. The project follows Mumbo’s earlier work reviving the Famicom Network System, an obscure Japan-only online service for the NES’s sister console — a similar pattern of resurrecting a piece of Nintendo hardware history that either never shipped widely or never shipped at all.
The firmware isn’t public yet. Mumbo’s FMV decoding currently leans on semi-reverse-engineered code borrowed from a “Bad Apple”-on-NES demo by developer Something Nerdy, and a cleaner, stripped-down release — limited to CD audio playback rather than full video — is planned before the code goes up publicly. The hardware design and a full build demonstration, however, are already out.