Legal Status of Emulation

This page will try and document some notable incidents regarding the legal status of emulation. Nothing in this page should be considered a replacement for lawyer advice.

Notable Legal Incidents

Nintendo

Direct legal action

1992 - Atari Games vs. Nintendo

Action: Pre-emptive lawsuit from Atari Games. Lawsuit against Atari Games for making new hardware copying the functionality of Nintendo's lock-out system, the 10NES, meant to prevent the NES from loading unauthorized game cartridges

Reason: Atari tried to reverse-engineered it, got a leaked copy of the 10NES source code after lying to the US Copyright Office (!), and then replicated it to make new games. Nintendo sued for patent infringement, copyright infringement.

Outcome: Settlement, although the courts ruled in favor of "reverse-engineering being fair use" it was tainted by the copyright-infringing way Atari acquired the source code. Nintendo settled and shifted their legal strategy as it was embroiled in other lawsuits regarding its monopolistic behavior.

1994 - Game Genie vs. Nintendo

Action: Pre-emptive lawsuit from Galbo. Lawsuit.

Reason: Created an unauthorized NES dev kit. Nintendo argued that the Game Genie violated their intellectual property, infringing on their exclusive right to make derivative works of their copyrighted games. Nintendo relied on a precedent where a third-party company selling a speed-up kit for the Galaxian arcade game lost, but that was because the speed-up kit itself included copyrighted content from Galaxian.

Outcome: Nintendo lost. Deterred litigousness against third party publishers. Altering the output of videogames was considered a case of "fair use". HOWEVER, they successfully lobbied for a similar law in Japan. As a result, devices that allow for cheating and patching them are outlawed there, with Konami going after people selling modified save files for Tokimeki Memorial in 1997. However, Nintendo's overly-aggressive actions against the doujin scene in 1999 triggered some public backlash that forced them to dial it down. Nintendo later collaborated with third party accessory publishers, but not for cheating devices.

February 1999 - UltraHLE (N64) vs. Nintendo

Action: Lawsuit against authors, Website Takedown

Reason: "Designed solely to play pirated copyright-infringing ROM copies"

Outcome: Discontinued project, developers killed their online presence, but the source leaked later in 2002 and was continued as UltraHLE 2064. Other better emulators appeared in the meanwhile.

Also notable for its time, UltraHLE was capable of playing commercial games while the console was still commercially viable, a feat which was ultimately noticed by Nintendo. In February 1999, Nintendo began the process of filing a lawsuit against the emulator's authors, along with the website hosting the emulator. Speaking to PC Zone, Nintendo representative Beth Llewellwyn commented: "Nintendo is very disturbed that RealityMan and Epsilon have widely distributed a product designed solely to play infringing copies of copyrighted works developed by Nintendo and its third-party licensees. We are taking measures to further protect and enforce our intellectual property rights which, of course, includes the bringing of legal action." Despite this, UltraHLE had grown beyond either its authors' or Nintendo's control. Subsequently, Epsilon and RealityMan abandoned their pseudonyms and went silent.

2003 - GBA/LCD screen ghosting technique

Action: Nintendo patented a technique used by PocketNES, a NES emulator targeting GBA screens.

Reason: Nintendo was also developing their own NES emulation solution for GBA screens, the so-called overpriced Classic NES Series. They took the fan-developed technique and patented it.

Outcome: No action ever taken against the emulator,

June 2014 - GB/GBC/GBA Patents

Action: Patent for all GB/GBC/GBA emulators on all devices, for game-specific speed-hacks (using hashes)

Outcome: Not actionable (prior use), never used, expired

2023 - Dolphin (GameCube) / Valve vs. Nintendo

Action: Dolphin submission to Valve, in order to make it available there. Valve doesn't immediately approve it, and asks for Nintendo's feedback. Nintendo answer back, requesting a rejection from Valve.

Reason: Dolphin including AES keys in the code (deemed "circumventing DRM, breaching DMCA")

Outcome: Valve rejected Dolphin from Steam, with no further actions.

2024 - Yuzu (Switch) vs. Nintendo

Action: Massive lawsuit against the for-profit LLC that manages Yuzu and its Patreon

Reason: Emulation and personal backups itself (mentioned in passing), Encouraging and engaging in piracy of unreleased leaked games and prominently profiting off it, Yuzu not including AES keys but using them to load encrypted game images, using Nintendo imagery to promote their patreon. Comparisons presenting the emulator as the better alternative. Included guides for unlocking the protection of Switch hardware on the emulator website.

Outcome: Settlement. Both Citra (also under the same team and LLC) and Yuzu's online presence and development is discontinued. Developers pay Nintendo $2.4m, retire from all emulation projects (even mGBA and Dolphin), issue statements denouncing emulation (in public) and claiming any emulation that deals with AES keys is illegal (in front of a federal judge, in an attempt to build up a legal precedent, despite cases like Accolade vs. Sega where similar protection circumvention wasn't deemed illegal because it preserves competitivity and interoperability - also protected by the DMCA itself), submit telemetry information to Nintendo, submit personal Switch hardware, avoid discovery (for even worse shady stuff specific to the Yuzu/Citra project) and run off with their personal salaries from the project in the sunset.

Pressured

2014-2015 - Dolphin (GameCube) / Project M vs. Nintendo

Action: The word "Project M" is bannable on the Miiverse. Had Twitch reject streams of the mod. Later in 2022, official tournament guidelines from Nintendo included "forbidden from using modified versions of Nintendo games". However, no DMCA was ever issued against the project.

Reason: Relies on emulation. Mod.

Outcome: Project M was abruptly shut down in 2015. The developers went on to develop their own fighting game.

2023 - Yuzu (Switch) / various Youtube channels vs. Nintendo

Action: Copyright takedown notices against videos promoting emulation of the Nintendo Switch for the following cases: Kotaku (game journalists) encouraging people to pirate leaked copies of Metroid Dread and Zelda Tears of the Kingdom after Nintendo denied them review copies (NoA took down the very video used in the article), Multiplayer mod for Zelda Breath of the Wild promoted on the Youtube channel of the mod author, and others.

Reason: Generic copyrighted audiovisual content DMCA justification (Game footage)

Outcome: No further retaliation from Nintendo against either Yuzu or the YT channels. Zelda Multiplayer mod shut down the project pre-emptively to avoid further trouble.

Technological measures

1994 - SNES

Select games trigger their anti-piracy without the proper save type, and actively try to mislead emulators and flashcarts. Worked around with SNES rom headers first, then a list of game-specific hacks.

2004 - GBA

Select games (Classic NES Series, a series of $40 individual NES games on the GBA) go out of their way to detect emulator behavior and refuse to boot up.

Select games refuse to load without the proper save type, and actively try to mislead emulators and flashcarts. Worked around with a list of game-specific hacks.

2010 - DS

Select games (a Konami life-sim for example) check for memory read speeds and trigger lockouts.

2012 - Wii

Select games (late-gen Disney) actively check for emulator presence and refuses to boot-up. An ex-developer offered his assistance to the Dolphin team to work around the issue, but they refused it, citing clean room reverse engineering best practices.

2023 - Nintendo Switch

Irdeto (Denuvo, with a Sony stake) offered anti-emulation services to Nintendo third-parties. While Nintendo approved them as an authorized developer, no games yet made use of this.

Collaboration

In the meanwhile, Nintendo and its partners hired multiple emulation developers to help with official products. Starting all the way back in the early 2000s with the individual who helped with the iNES specification who was later involved in NES emulation on the GameCube, Game Boy Advance, e-Reader and the Virtual Console services. Nvidia (for the Nvidia Shield Chinese edition which included GameCube emulation) and NERD (for Nintendo Switch services and remasters) openly hired "emulator" developers.

Nintendo also offered bounties to people behind 3DS/Wii U/Switch exploits to disclose their exploits for them to patch, while suing others who chose to profit off it in ways they didn't approve off.

Tolerated

Nintendo developers clearly follow the emulation scene closely, as some updates were made to remove mentions of unofficial N64 memory setups they accidentally included, and leaks for NERD's GBA emulation on the Nintendo Switch clearly mentioned unofficial software. Oblique allusions by Miyamoto and other staff acknowledged how games like Star Fox 2 and Mother 3 were known about in the West, wondering whether is it "better off left that way". Some unofficial emulation artifacts used internally by Japanese Nintendo employees even made it accidentally to the product, and one Nintendo PR staff accidentally compared a Super Mario Maker level to a "romhack".

Similarly, multiple third-party publishers for Nintendo consoles openly use emulators developed from fan sources. This contrasts with the language used on their website that claims "all emulation is illegal". Although it's true that Nintendo used to reject some emulated collections (for Atari games) on the Nintendo DS, it's not clear whether it's out of an anti-emulation stance or unrelated quality control issues tied to the quality of the collection itself. Nintendo never went after third party publishers that made Nintendo-exclusives available on other consoles, neither did Sony the other way around, although that might be to avoid anti-competitive behavior and lawsuits with emulations.

Direct legal action

1999 - Bleem! (PS1) vs. Sony

Action: Lawsuit (lost, but crippling Bleem financially). Threats to retailers selling Bleem. Second lawsuit.

Reason: Paid Emulator. Unfair competition (runs on DreamCast and PC). Using Sony imagery to promote their product in print ads. Comparisons presenting the emulator as the better alternative. Circumvents/includes BIOS. Patent infringement.

Outcome: Sony lost the BIOS/unfair competition lawsuit for the PC version, however it was a pyrrhic victory for Bleem who went bankrupt soon after. The emulator was leaked afterwards. Some of the staff was hired by Sony to work on the official PS1 emulation for the PSP. Established a legal precedent.

1999 - Connectix VGS (PS1) vs. Sony

Action: Lawsuit.

Reason: Paid emulator. Copyright Infringement.

Outcome: Sony lost the lawsuit, but until then was awarded a temporary injunction that prevented the emulator's sale. Sony brought VGS and then discontinued it. Some of the staff was hired by Sony to work on the official PS1 emulation for the PSP. Established a legal precedent.

November 2017 - RPCS3 (PS3) / Patreon vs. Atlus

Action: DMCA takedown against the project Patreon

Reason: Circumvents DRM protections, promotes the availability of a specific game (Persona 5) on PC platforms, using Atlus imagery to promote their patreon

Outcome: No lawsuit or further action by Atlus, besides a damage control statement on their forums. Emulator development continued. After discussions with Patreon, all Persona 5 imagery was removed and its page in the compatibility list renamed to "[Untitled]" (later reverted) and the emulator developers treating that game's name like Voldemort for a while.

Atlus Games attempted a DMCA strike on the Patreon account used for the RPCS3 project. This was unusual because the PS3 was at the tail-end of its console generation, and Atlus was the one initiating the legal procedure rather than Sony. As it turns out, Persona 5 released in late 2016 and was commonly cited by Sony management as a very important exclusive. The game would never see release on either PC or other platforms until 2022, and Persona 5 marketing often encouraged fans of the game to buy a PlayStation 4 - a console struggling to sell in Japan back then. It's no surprise that Atlus (and possibly Sony) would be upset that PC users would settle for the emulated PS3 version instead. In their words: “The PS3 emulator itself is not infringing on our copyrights and trademarks; however, no version of the P5 game should be playable on this platform; and [the RPCS3] developers are infringing on our IP by making such games playable”.

Collaboration

Hired ex-Bleem/VGS staff for the PS1 emulation on PSP, and licensed a fan emulator for the PS Classic collector hardware.

Sega

While ambivalent towards emulators ever since they went third-party (except for the RPCS3 case, technically, as Atlus was under Sega at the time) that wasn't always the case.

Direct legal action

1993 - Sega vs. Accolade

Action: Lawsuit against a third-party cartridge developer and game developer.

Reason: Decompiled Sega's DRM to provide their own running copy, included Sega trademarks (the name, in Nintendo's case images) required for the game to work

Outcome: Sega lost. Decompilation of Sega's software, and the required trademark infringement to ensure interoperability, was considered "fair use", establishing a precedent for reverse-engineering in general, and emulation as a whole by proxy. Sega ultimately settled with Accolade and granted them publishing privileges.

Collaboration

While Nintendo and Sony sued the most successful PS1 emulators in the 5th Gen, Sega had a more novel idea to shut down Saturn emulation. GiriGiri is a proprietary Sega Saturn emulator and one of the first to run commercial games at a decent speed. The developer, MegaDeath, was hired by Sega and GiriGiri was made an official emulator under the CyberDisc service. The service only lasted a little over a year before it was shut down in early 2004.

Sega also provided an online service on the DreamCast (but only in Japan) offering emulated versions of Sega Genesis, Sega Master System, but also even NEC PC Engine games, years before the Wii Virtual Console was even a thing. Only a single disc covering Sega Genesis emulation was released in the US, with leftover instructions on the disc by the developer addressed to people pirating the game and encouraging them to try other Sega Genesis games, including their proper compatibility settings.

Sega later collaborated with a huge number of fan emulation developers for their countless retro collections, both from Japan and elsewhere. Albeit some exclusive content was later on tampered with to prevent its compatibility with third-party emulators, to limit piracy and unauthorized resellers. Ex-Sega of Japan developers also worked on fan emulators. A lot of developer interviews by Sega developers discuss common emulation topics like input delay and CRT shaders and screen scales.

Apple

Quite infamously, Apple hires anyone behind a promising iPhone emulator or compatibility layer, and it almost always gets shut down and scrubbed off the face of the Internet.