Nintendo's ongoing war against Switch emulation is quietly waging, as the company continues to play a game of DMCA whack-a-mole with anyone forking the now unavailable Yuzu project on GitHub. Nintendo stirred up significant controversy earlier this year after the developers of the popular Nintendo Switch emulation tool announced that they were ceasing development in the wake of ongoing legal challenges by Nintendo.

Nintendo has been targeting Yuzu forks

The Yuzu codebase is a toxic copyright

Earlier this year Nintendo effectively forced developers of Switch Emulator Yuzu to cease development following a string of lawsuits. Yuzu was forced to settle out of court for a significant sum ($2.4M), and all distribution of the popular emulation software has ceased. Prior to this, Yuzu was one of the most popular emulators for the Nintendo Switch.

In the aftermath of that lawsuit, Nintendo has been using the DMCA to aggressively pursue takedowns against anyone forking or modifying Yuzu's code, as well as against existing distribution methods. On GitHub alone, over 8000 forked versions of the source code (seemingly without much consideration for the extent of modification) were taken down last week. This takedown was so widespread because GitHub automatically disables all forks of a given repository when its parent is taken down.

Other Switch emulators are still available

Yuzu is far from the only emulator on the internet

While Nintendo originally targeted Yuzu, other emulators have remained available. There seems to be reasoning behind this - it's long been claimed that Yuzu uses illegally acquired cryptographic keys and source code from a Nintendo Switch dev kit in order to circumvent Nintendo's TPMs (technological protection measures). This, combined with the fact that Yuzu were charging a subscription fee for early access builds of the project, may have brought more attention from Nintendo than has been afforded to other popular forks.

The DMCA notice published on GitHub would seem to confirm this, including the following quote under the heading "How is the accused project designed to circumvent your technological protection measures?"

Specifically, yuzu illegally circumvents Nintendo’s technological protection measures and runs illegal copies of Nintendo Switch games. Nintendo Switch games are encrypted using proprietary cryptographic keys (prod.keys) which protect against unauthorized access to and copying of the copyrighted games. During operation, yuzu necessarily uses unauthorized copies of these cryptographic keys to decrypt unauthorized copies of Nintendo Switch games, or ROMs, at or immediately before runtime without Nintendo’s authorization.

As Yuzu settled out of court with Nintendo, the true extent of Nintendo's claims has never been publicly validated.

Other popular emulators, such as Ryujinx, are still under development and available to download. Other such emulators, namely Suyu and Sudachi, have been targeted by Nintendo separately. Discord shutdown servers for both emulators and banned the accounts of several developers, as reported by The Verge. Discord was not forthcoming in explaining whether the servers and accounts had been banned because of a perceived association with Yuzu, or because of their actions relating to Suyu and Sudachi.

The legal state of emulation has always been murky

Emulation has always been in a murky state legally, as we've covered previously on XDA. Ultimately, Nintendo's TPMs mean that any game running on unofficial hardware will need some kind of illegal circumvention — as Nintendo themselves provide no means for legally certifying an emulator or alternative piece of hardware, nor gaining access to the encryption keys needed to rip a game yourself.

As well explained by GamesRadar+, Nintendo is using a little-known part of copyright law, as well as a liberal (but so far accepted) interpretation which means that any tooling designed with the intention of avoiding its TPM measures is automatically illegal. This interpretation has been used to go after other popular tools used in ripping and cloning Switch games, namely SigPatch-Updater and LockPick.

Nintendo Wii emulators have had similar problems

The Dolphin emulator generated plenty of controversy in 2023👁 dolphin emulator

This argument has been fought out before, in a range of ways, but it leaves emulators in a sticky position. Last year, Dolphin Emulator, the popular Nintendo Wii emulator, announced it would be released on Steam. Valve blocked this after contact with Nintendo, and instead required that Dolphin come to an agreement with Nintendo themselves. The sticking point here was the Wii's Common Key - a common encryption key stored in hardware on all Nintendo Wii's and used to decrypt the disc. This key had been public knowledge for years, and there were no significant consequences for Dolphin, but their blog post at the time illustrates what a precarious legal situation Dolphin is in regarding the continued distribution of Nintendo's private keys.

In their blog post, the Dolphin developers explain that they don't actually think that they are in any legal jeopardy, and have taken legal advice on the matter in the past. Again though, this argument hasn't yet been tested in court.

Nintendo is keeping the line deliberately grey

Emulation projects are being forced to operate in murky waters

The nature of Nintendo's recent DMCA activity, and Dolphin's rejection from Steam, makes it extremely hard to truly predict where the line for what Nintendo considers acceptable or not is. It's not clear whether Nintendo is coming out against all emulation. It's possible that Nintendo is trying to control emulation in a way which avoids the potential of a court-standoff which could galvanize the community and end up adding legal precedent to support the case of emulation.

Including proprietary source code is obviously a no-no, but Dolphin's ongoing survival and Yuzu's demise leave open questions about how to legally acquire and make use of encryption keys. Similarly, Nintendo's aggressive efforts against projects threatening the Switch's TPM elsewhere leave all emulation potentially in danger of the DMCA. The impact of Yuzu's commercialization on Nintendo's actions also isn't clear.

Yuzu is dead, but more will live on

In the aftermath of this, emulation projects are keen to avoid drawing attention to themselves (as reported by The Verge) and potentially provoking the wrath of Nintendo; likely in a tacit admission that if the Goliath of gaming were to come knocking, they (like Yuzu) may not have access to the funds required to mount their legal defense. The other danger for these companies, as Bleem unfortunately found out in the 1990s, is that an effective defense is no guarantee of long-term survival.

Despite the uncertain future for emulation, I'm quietly confident. Nintendo, despite largely being immune from the worries of public opinion, seems cautious that the all-out war on emulation will provoke significant backlash; a backlash that could lead to legal pressures or changes to clarify the position of emulation and software archiving. We'll have to wait and see what the teased Switch 2 offers in this regard, but it'll almost certainly have a new set of locked down copy protection measures.