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  • Writer's pictureLewis Sorokin

Nintendo v. Yuzu: an encryption and emulation melee

Updated: Apr 11

Nintendo of America has sued Tropic Haze LLC, the makers of a popular Nintendo Switch emulator called Yuzu, alleging that they are engaging in circumvention of the Digital Millenium Copyright Act (DMCA) and facilitating piracy. The complaint, filed in the United States District Court for the District of Rhode Island, alleges Trafficking in Circumvention Technology under three different sections of the DMCA, and both direct and indirect liability for infringement of Nintendo’s copyrights in its games and consoles.

Nintendo’s complaint cites examples of Reddit communities expressly built around using Yuzu for piracy, and discusses the Yuzu development team’s track record of compatibility for new games at or before release. Nintendo also tells the story of over one million fans online playing leaked copies of the highly-anticipated 2023 game The Legend of Zelda: Tears of the Kingdom on the Yuzu emulator several days before its release. Nonetheless, it also discusses that Yuzu’s lead developer banned pre-release discussion of the game in the Yuzu Discord server. The Yuzu team did not add support for the game into its official builds until the game’s release; rather, users took advantage of the emulator being open source and created their own custom builds of the emulator which were compatible with the leaked Zelda ROMs. While these custom builds and the leaked copies of the game certainly almost constitute copyright infringement, Nintendo likely has an uphill battle tying these issues back to Yuzu’s team, as the sole defendant.

Stepping back to the issue of whether the emulator itself should be a source of liability, there is plenty of case law on the books establishing that reverse engineering is legal under copyright law. At the same time, there is case law supporting the efforts of DRM and other counter-piracy measures like Nintendo puts into its modern consoles and games. Nonetheless, Nintendo’s claims of Trafficking in Circumvention Technology center around Yuzu’s promotion of tools including “TegraRcmGUI,” “Lockpick_RCM,” and “NXDumpTool” specially designed to access Nintendo’s proprietary cryptographic keys called “prod.keys.” Without these keys, which are stored on Nintendo Switch consoles, bootlegged Switch games cannot be decrypted and would be unplayable. Yuzu’s website includes instructions on how users can access these system files on a Switch console and use them to set up the emulator, and Yuzu users regularly discuss “decrypted” copies, which Nintendo does not condone in general. In all likelihood, there are additional questions which will not be answered until after discovery.

I like Nintendo. I have played Nintendo games since my fifth birthday and never looked back. But I also know how protective Nintendo is of its IP from my work for Did You Know Gaming, a popular YouTube channel about video game history and trivia. In 2022, DYKG was met with a DMCA claim for a video they put together with never-before-told stories about a cancelled Zelda title, Heroes of Hyrule. We successfully defended that video on First Amendment grounds, and it remains public to this day.

While it is difficult to say what lies ahead, the road for the Yuzu team will be no rainbow. I do not expect Nintendo to go down without a brawl.


Update March 4, 2024: Nintendo and Yuzu have jointly agreed to enter a judgment in favor of Nintendo, including $2.4M and a permanent injunction against Yuzu. Now the question, can Nintendo collect that award, or is Yuzu judgment-proof?

Image attribution: Creative Commons license, from


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