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.”
Just Follow These (Complicated) Instructions
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.
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 Common Key used to decrypt game files.
Absent the inherent ability to break DRM, an emulator would generally be covered by decades of legal precedent establishing the right to emulate one piece of hardware on another using reverse-engineering techniques. But Yuzu’s “bring your own decryption” design is not necessarily a foolproof defense, either.
Nintendo’s lawsuit makes extensive reference to the Quickstart Guide that Yuzu provides on its own distribution site. That guide gives detailed instructions on how to “start playing commercial games” with Yuzu by hacking your (older) Switch to dump decryption keys and/or game files. That guide also includes links to a number of external tools that directly break console and/or game encryption techniques.
Through these instructions, Nintendo argues in its complaint, “the Yuzu developers brazenly acknowledge that using Yuzu necessitates hacking or breaking into a Nintendo Switch.” Nintendo also points to a Yuzu Discord server where emulator developers and users discuss how to get copyrighted games running on the emulator, as well as publicly released telemetry data that shows the developers were aware of widespread use of their emulator for piracy (as the Yuzu devs wrote in June 2023, “Tears of the Kingdom is by far the most played game on Yuzu”).
While Loiterman says that “instructions and guidance are not circumvention,” he added that “the more layers of indirection between Yuzu’s software and activity and distribution of the keys the safer they are. The detailed instructions, the Discord server, and the knowledge of what all this is used for are at least problematic.”
“Whether Yuzu can get tagged with [circumvention] simply by providing instructions and guidance and all the rest of it is, I think, the core issue in this case,” he continued.
In a response on the Yuzu Discord, the development team wrote, “We do not know anything other than the public filing, and we are not able to discuss the matter at this time.”
What About My Backup Copies?
In its lawsuit, Nintendo argues that “there is no lawful way to use Yuzu to play Nintendo Switch games.” But that statement has a few potential holes that could serve as possible defenses for the emulator maker.
For one, the US Copyright Office generally allows users to make copies of legitimately purchased software for archival purposes, with a few basic caveats. Accessing such personal archival copies would potentially be a legal use for an emulator like Yuzu.
Nintendo goes directly after this argument in its lawsuit, arguing that buying a Switch game only means you “have Nintendo’s authorization to play that single copy on an unmodified Nintendo Switch console.” Any other copy is, by definition, an “unauthorized copy,” Nintendo says, even if it’s made by the original purchaser for their own personal use.
What’s more, Nintendo argues that using Yuzu as a way to play legitimate Switch purchases on another platform (e.g., an Android device or Windows machine) is also forbidden. “Nintendo has the right to decide whether or when to enter the market of games for platforms other than its own console,” the company writes.
In this, Loiterman thinks Nintendo’s arguments probably go too far. “Nintendo wants to say that the license agreement for all users restricts their use of the game to only run on the Switch,” he told Ars. “That’s problematic because the 37 CFR § 201 includes a number of exceptions and limitations on how far-reaching and applicable licensing terms like that can be.”
Homebrew and Accessibility
Yuzu defenders could also point to the emulator’s ability to run a wide variety of homebrew Nintendo Switch games and software, ranging from weather-tracking apps to an obligatory Doom port. Running this software through Yuzu is a legitimate use that doesn’t require breaking Nintendo’s encryption or software copyrights.
In its lawsuit, though, Nintendo argues that “the vast majority of Yuzu users are using Yuzu to play downloaded pirated games in Yuzu.” For instance, the lawsuit points to data showing that leaked copies of The Legend of Zelda: Tears of the Kingdom were downloaded 1 million times in the week and a half before the game’s release, a time period that also saw “thousands of additional paid members” added to Yuzu’s Patreon. Yuzu is “secondarily liable” for “inducing” this kind of infringement, Nintendo argues.
Inducement arguments aside, the presence of some legal homebrew uses could help Yuzu here. “We have plenty of objects that can be used in either legal or illegal ways that are not illegal to own or use,” attorney and game industry analyst Mark Methenitis told Ars. “Lockpicks, for example, have perfectly legitimate use cases as well as illegal ones, and we don’t restrict ownership of lockpicks … But these are the balancing acts a finder of fact has to consider in the context of all of the arguments presented.”
But this isn’t a foolproof defense, either. “Alternative uses certainly help, and more research might reveal some interesting precedents, but I’m skeptical that enabling homebrew alone is going to be a shield if the court finds anti-circumvention or trafficking [under DMCA],” Loiterman said. When it comes to legitimate homebrew use cases, “I would say ‘the more the better,’ [but legally] I doubt there’s a clear, bright line rule on that.”
Yuzu’s developers could also argue for the emulator’s existence as a tool to help make Switch games accessible to individuals with disabilities that prevent them from directly using Switch hardware. In its 2021 DMCA exemption rulings, the Copyright Office allowed for circumvention that “enable[s] individuals with disabilities to use alternate input devices to play video games.”
“I think Nintendo may have a hard time arguing against legitimate use cases [like accessibility],” Methenitis said. “Related to the argument, of course, will be the question of how accessible is the console to begin with… but I will also acknowledge you can do a lot more, and potentially reuse other accessibility devices or software, when running something on a PC.”
To argue this exemption in court, though, “Yuzu would need to point to some actual example of accessibility,” Loiterman said. “I don’t think the idea that accessibility might be enabled or improved in the abstract is going to be enough.”
A Warning Shot
At this point, Nintendo has a well-established track record of defending its copyrighted works by going after fangames, ROM distribution sites, and hardware modders. But the makers of emulators themselves have generally been safe from Nintendo’s legal ire until now.
Nintendo’s lawsuit, if successful in court, could set a new precedent that would have worrisome and far-reaching implications for pretty much every other emulator developer out there. But Loiterman said he’s “skeptical this goes to trial. Unless Yuzu has very deep pockets, I think they’re likely to take it down, and the software will live on but not be centrally distributed by Yuzu.”
That kind of takedown under threat of lawsuit could still provide an easy blueprint for other console makers who wanted to put up legal roadblocks for emulation development. But the case against Yuzu is also somewhat distinct in dealing with emulation of a console that is still selling significant amounts of software and hardware. That makes Nintendo’s business case for going after Yuzu a little different from, say, Sony’s potential impetus for going after the makers of a PSP emulator in 2024.
“[Nintendo] must feel this is a significant piracy risk to bring this case to begin with,” Methenitis points out. And while Methenitis said that legal challenges to emulators “by and large … haven’t been successful in the past,” he said Nintendo might be legally emboldened by cases like Blizzard’s successful suit against World of Warcraft bot WoWGlider and Bungie’s recent successful lawsuits against Destiny 2 cheat makers.
“I do see this as a threat in practical terms, if not legal,” Loiterman added. “Nintendo isn’t attacking the core concept of emulation’s legality. They are attacking the tools and techniques that you need to make emulation actually work. There’s a whole chain of things you need to make emulation work and Nintendo doesn’t need to destroy every link in the chain.
“While I don’t think this is a slam dunk (few lawsuits are), I wouldn’t want to be on the other end of this lawsuit either,” he added.
This story originally appeared on Ars Technica.
