How To Add More Games to the NES Classic

The hype around the NES Classic in 2016 was huge, and as expected, units are already selling for excessively high prices on eBay. The console shipped with 30 games pre-installed, primarily first-party releases from Nintendo. But worry not — there’s now a way to add more games to your NES Classic!

Like many a good hack, this one spawned from a forum community. [madmonkey] posted on GBX.ru about their attempts to load extra games into the console. The first step is using the FEL subroutine of the Allwinner SOC’s boot ROM to dump the unit’s flash memory. From there, it’s a matter of using custom tools to inject extra game ROMs before reburning the modified image to the console. The original tool used, named hakchi, requires a Super Mario savegame placed into a particular slot to work properly, though new versions have already surfaced eliminating this requirement.

While this is only a software modification, it does come with several risks. In addition to bricking your console, virus scanners are reporting the tools as potentially dangerous. There is confusion in the community as to whether these are false positives or not. As with anything you find lurking on a forum, your mileage may vary. But if you just have to beat Battletoads for the umpteenth time, load up a VM for the install process and have at it. This Reddit thread (an expansion from the original pastebin instructions) acts as a good starting point for the brave.

Only months after release, the NES Classic is already a fertile breeding ground for hacks — last year we reported on this controller mod and how to install Linux. Video of this ROM injection hack after the break.

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Tweeting From The NES Expansion Port

[Trapper] is an 80’s kid, and back in the day the Nintendo Entertainment System was his jam. One fateful night, he turned over his favorite gray box, removed a small plastic guard, and revealed the mythical expansion port. What was it for? What would Nintendo do with it?

The expansion port on the NES wasn’t really used for anything, at least in the US market. Even in the homebrew scene, there’s only one stalled project that allows the NES to connect to external devices. To fulfill [Trap]’s childhood dream, he would have to build something for the NES expansion port. Twitter seemed like a good application.

The first step towards creating an NES Expansion Port Twitter thing was to probe the depths of this connector. The entire data bus for the CPU is there, along with some cartridge pass-through pins and a single address line. The design of the system uses a microcontroller and a small bit of shared SRAM with the NES. This SRAM shares messages between the microcontroller and NES, telling the uC to Tweet something, or telling the NES to put something on the screen.

Only a single address pin – A15 – is available on the expansion port, but [Trapper] needed to read and write to a certain section of memory starting at $6000. This meant Addresses A13 and A14 needed to be accessed as well. Fortunately, these pins are available on the cartridge slot, and there are a number of cartridge pass-through pins on the expansion connector. Making a bridge between a few pins of an unused cartridge solved this problem.

From there, it’s just a series of message passing between a microcontroller and the NES. With the help of [Trap]’s brother [Jered] and a Twitter relay app running on a server, this NES can actually Tweet. You can see a video of that below.

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