Nintendo Sues Makers of the Wildly Popular Yuzu Emulator

Nintendo has filed a lawsuit against Tropic Haze, the makers of the popular Yuzu emulator that the Switch-maker claims is “facilitating piracy at a colossal scale.”

The federal lawsuit—filed Monday in the District Court of Rhode Island and first reported by Stephen Totilo—is the company's most expansive and significant argument yet against emulation technology that it alleges “turns general computing devices into tools for massive intellectual property infringement of Nintendo and others' copyrighted works.” Nintendo is asking the court to prevent the developers from working on, promoting, or distributing the Yuzu emulator and requesting significant financial damages under the DMCA.

If successful, the arguments in the case could help overturn years of legal precedent that have protected emulator software itself, even as using those emulators for software piracy has remained illegal.

«Nintendo is still basically taking the position that emulation itself is unlawful,» Foundation Law attorney and digital media specialist Jon Loiterman told Ars. «Though that's not the core legal theory in this case.»

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The bulk of Nintendo's legal argument rests on Yuzu's ability to break the many layers of encryption that protect Switch software from being copied and/or played by unauthorized users. By using so-called prod.keys obtained from legitimate Switch hardware, Yuzu can dynamically decrypt an encrypted Switch game ROM at runtime, which Nintendo in its lawsuit argues falls afoul of the Digital Millennium Copyright Act's prohibition against circumvention of software protections.

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Crucially, though, the open source Yuzu emulator itself does not contain a copy of those prod.keys, which Nintendo's lawsuit acknowledges that users need to supply themselves. That makes Yuzu different from the Dolphin emulator, which was taken off Steam last year after Nintendo pointed out—and Dolphin Team confirmed—that the software itself contains a copy of the Wii