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Is Reverse-Engineering a Game Legal? AI Recomps, Publisher Takedowns, Copyright Terms and Whether to Update Your PS5 (2026)

Not legal advice, not a how-to: how Take-Two, Activision, Bethesda, Nintendo and Sony responded to reverse-engineered games, fair use vs copying, bring-your-own-files ports, copyright terms vs patents, and why to keep your PS5 on 14.10.

T Terapep ·

TL;DR: Rebuilding a commercial game by reverse engineering, whether AI does it or people do, is not automatically legal and not automatically illegal. US courts have allowed copying that is only a step toward compatible, original code (Sega v. Accolade, Sony v. Connectix). Shipping copied code, art, music, characters or levels is a different matter. In practice, publishers rarely wait for a court. Take-Two, Activision, Bethesda and Nintendo have all used DMCA notices, cease-and-desist letters or lawsuits to remove projects. Projects that ship only new code and make you supply your own game data have lasted longer than ones that hand out the whole game. That still doesn't make them legally safe. Game copyrights will not expire for decades (patents do, after about 20 years). And yes: keep your PS5 updated. As of 12 Oct 2026 the current version is 14.10.

Last checked: 12 Oct 2026 (KST). This follows yesterday's explainer, AI game cheats, the PS5 Relapse jailbreak and AI-rebuilt games, which has the full timeline. This is general information, not legal advice. Laws differ by country and the facts of each case matter. If you are building or distributing something, talk to a lawyer where you live. It is also not a how-to. It contains no decompilation, extraction, dumping, decryption, jailbreak or cheat steps, and no download links for ports, ROMs or tools.

1) Is AI-recompiled or reverse-engineered game work legal?

How publishers have actually responded

Company Project Date Action Outcome Source
Take-Two re3 / reVC (reverse-engineered GTA III / Vice City source code on GitHub) 19 Feb 2021 (DMCA); Sep 2021 (lawsuit) DMCA takedown to GitHub. The developers counter-noticed, and Take-Two then sued them, saying they "slavishly recreated the original code" Confirmed: GitHub processed the notice against 861 repositories (the parent repo and its forks). We found no public final ruling in the sources we checked GitHub DMCA notice, GitHub legal-action notice, TorrentFreak
Take-Two Browser port of GTA: Vice City on DOS Zone Dec 2025 Takedown notice from Ebrand on Take-Two's behalf. It said asking users to enter data from original copies "may constitute circumvention of technological protection measures" Confirmed: taken down, even though it required users to own the game Tom's Hardware, XDA
Activision AI-assisted decompilation of Modern Warfare 2 (PC) by Maurice Heumann 30 Sep 2026 Footage on X replaced with "This media has been disabled in response to a report by the copyright owner" Confirmed: footage disabled and the linked code site unreachable. The developer later said "none of the code will be shared" Kotaku, Heumann's blog
Bethesda "Fallout: New York", an AI-coded browser game in Fallout style 1 Oct 2026 Alleged cease-and-desist, according to the creator, who posted a screenshot Creator abandoned the project. Bethesda hasn't commented publicly in the sources we found Kotaku
Nintendo Super Mario 64 PC port (leaked compiled build) May 2020 Copyright complaints via Wildwood Law Group against file hosts, Google links and YouTube videos. They called it "an unauthorized derivative work" Confirmed: some hosts and videos removed. The decompiled source project itself wasn't the target TorrentFreak, VGC
Nintendo RomUniverse (ROM download site) 2019 suit; May 2021 judgment Copyright and trademark lawsuit Confirmed: $2.115M in statutory damages; site owner ordered to destroy pirated games TorrentFreak, Ars Technica
Nintendo Yuzu (Switch emulator) Feb–Mar 2024 DMCA anti-circumvention lawsuit Confirmed: $2.4M settlement, permanent injunction, domain handed over The Verge, court judgment (PDF)
Nintendo Ship of Harkinian (Ocarina of Time PC port) 2022 onward None reported in the sources we checked Still public. In 2022 The Verge noted "no word from Kyoto" The Verge, GameSpot
Nintendo Zelda64Recomp (Majora's Mask native PC port via N64Recomp) May 2024 onward None reported in the sources we checked Still public. IGN's launch coverage notes the legal risk but reports no Nintendo action IGN
Sony Connectix Virtual Game Station (PlayStation emulator) 1999–2000 Copyright lawsuit Sony lost on appeal. The Ninth Circuit held that Connectix's intermediate copying of the BIOS during development was fair use EFF summary

What the table shows: in recent years these disputes have mostly ended outside court, through takedowns, letters and settlements. "Nobody has been sued" therefore doesn't mean "this is legal". It may only mean the rights holder hasn't acted yet. A missing takedown for Ship of Harkinian or Zelda64Recomp means only that none has been reported, not that Nintendo approves.

Legal concepts in plain language (not legal advice)

  • Copyright protects expression, not ideas. Code, art, music, text, character designs and level layouts are expression. The US Copyright Office says plainly: "The idea for a game is not protected by copyright. The name or title given to the game and the methods for playing it are not protected by copyright" (copyright.gov). Korea's Copyright Act defines a "work" as a creative production expressing human thoughts and emotions and lists computer programs as works (Copyright Act, Arts. 2 & 4, KLRI English text).
  • Reverse engineering to learn how something works can be fair use in the US, but only narrowly. In Sega v. Accolade (9th Cir. 1992), Accolade disassembled Genesis code only to learn the interface, wrote its own games, and "no Sega code was copied" in them. The court called that intermediate copying fair use. In Sony v. Connectix (9th Cir. 2000), the court reached the same answer for an emulator that didn't include Sony's BIOS code (EFF Reverse Engineering FAQ). Both cases turned on the final product being original. EFF warns that it is "highly risky to copy any code into a program you create as a result of reverse engineering".
  • Clean-room reimplementation is the classic way to limit that risk. One team studies the original and writes a purely functional specification. A separate team that never sees the original code writes new code from that spec. EFF lists this as a risk-reduction practice (EFF). An AI model fed the original program doesn't obviously give you that separation.
  • Anti-circumvention is a separate offence. In the US, DMCA §1201 bans getting around "technological protection measures" (encryption, authentication and similar) even when no copying is proven. Its interoperability exception is narrow (EFF). The Yuzu judgment rested on this, and Take-Two's Vice City notice cited it.
  • Contracts can waive rights you would otherwise have. In Blizzard v. BnetD (8th Cir. 2005), the court enforced a EULA ban on reverse engineering (EFF).
  • DMCA takedowns are notices to hosts such as GitHub, X and YouTube. The host usually removes first and leaves the uploader to file a counter-notice. That is why most of the actions in the table never reached a judge.
  • Exceptions vary by country. The US has open-ended fair use. Korea has its own fair-use clause with four factors similar to the US test (Art. 35-5) and separately defines "decompilation of program code" as reproducing or converting code to get information needed for compatibility of independently created programs (Art. 2(34)). The EU and other jurisdictions have their own, often narrower, interoperability rules. Being legal in one country doesn't make something legal everywhere it is downloaded.

Reader question: if I redraw the assets and retune the numbers, is it still infringement?

It can be. Copyright covers more than texture files. If the code (or its structure and organisation), the characters, the level layouts or the distinctive look and feel are copied, new art may not cure it. In Tetris Holding v. Xio Interactive (D.N.J. 2012), the court found a Tetris clone infringing. The ruling accepted that rules and mechanics are unprotectable, but held that the clone copied Tetris's specific visual expression, including piece shapes, board dimensions and on-screen elements (court opinion, GovInfo PDF). "Fallout: New York" claimed "zero texture files" and still drew an alleged Bethesda letter, because the Fallout name, world and signature features belong to Bethesda (copyright and trademark) (Kotaku).

What is generally not protected: a genre, a core mechanic, or a rule such as "match falling blocks to clear lines", written as original code with original art, names and levels (copyright.gov). That's why genre clones are everywhere. The line is about how much of the original's expression you take, not whether you swapped the PNGs.

2) Do game copyrights ever expire? (Patents do.)

Game code, art and music are protected by copyright. A few game mechanics have been protected by patents. The two work very differently.

Right What it covers in games How long Source
Copyright (US), studio/company work ("work made for hire") Code, art, music, text, characters 95 years from first publication or 120 years from creation, whichever ends first US Copyright Office
Copyright (US), individual author Same Author's life + 70 years (works created since 1978; older works vary) US Copyright Office
Copyright (EU) Same Author's life + 70 years (anonymous works: 70 years from publication) EUR-Lex summary of Directive 2006/116/EC
Copyright (Korea), individual Same Life + 70 years (Art. 39) Copyright Act, KLRI English text
Copyright (Korea), work made for hire (company) Same 70 years after being made public, or 70 years from creation if not made public within 50 years (Art. 41) Copyright Act, KLRI English text
Patent (US) A specific technical method, e.g. a gameplay or loading technique Generally 20 years from filing, if maintenance fees are paid USPTO
Trademark (US) Names and logos ("Zelda", "Fallout", "GTA") Can last forever while the mark is used and maintenance filings are made USPTO

What this means: commercial video games date from the 1970s at the earliest, and most are company works. Even under the shortest company-work terms above (70 years from publication in Korea, 95 years in the US), essentially no commercial game has fallen into the public domain because its term ran out. A 1996 N64 game is protected in the US until roughly the 2090s, and its name can stay trademarked indefinitely. "It's an old game, so it's free" is a myth. Abandonware is not a legal category.

Patents are the part that does expire. A real example is Namco's US patent 5,718,632, which covered playable "auxiliary" minigames during loading screens. It was filed in November 1995 and expired on 27 Nov 2015, after its 20-year term (EFF, Ars Technica, Google Patents record). After that, anyone could use the idea in the US. Namco's actual games, their code, art and Ridge Racer name, are still under copyright and trademark. Not legal advice.

3) "Bring your own game files" vs full redistribution

The structural difference

There are two very different kinds of projects behind the "PC port" headlines:

  1. Engine-only / bring-your-own-data projects. The project publishes only new code: a decompiled or recompiled engine, renderer and enhancements. It ships no original art, models, music or levels. The user must supply data from a copy they own. The Verge described Ship of Harkinian's download as "a sort of shell of the game … but none of the copyright-protected assets like character models, level maps, or music" (The Verge). A developer on the N64Recomp-based ports said the result "doesn't include assets and only requires a ROM to play" (IGN).
  2. Full redistribution. A ready-to-play package or web page that bundles the original assets, or the original code compiled together with them, so anyone can play without owning the game. Ready-made ROM downloads are the extreme case.

Which have been taken down, and which have survived

Type Example What happened Source
Full redistribution RomUniverse ROM site $2.1M judgment TorrentFreak
Compiled build circulating with game content Super Mario 64 PC port executable (2020) Hosts and videos hit with copyright complaints TorrentFreak
Browser-playable port (own-copy requirement claimed) DOS Zone Vice City (Dec 2025) Taken down; notice cited circumvention Tom's Hardware
Source code reconstructed from the original (no assets) re3 / reVC (2021) DMCA notice and lawsuit anyway TorrentFreak
AI decompilation MW2 (Sep 2026) Footage disabled; code not shared Kotaku
Engine-only, BYO data Ship of Harkinian; Zelda64Recomp Still public; no action reported The Verge, IGN

Takeaways:

  • Bundling the original assets is the clearest line. Every full-redistribution case above ended in removal or damages.
  • "Bring your own files" lowers the risk but doesn't remove it. re3 shipped no assets and was still sued over the code itself. The Vice City notice shows rights holders may argue that the "enter your own data" step is circumvention.
  • Survival is not permission. The Nintendo-game ports that are still up have no license, and neither has a reported court ruling behind it. They exist because the rights holder hasn't acted, or hasn't been reported to have acted.
  • Human decomp teams draw this line themselves. Kotaku reports the Zelda and Banjo recomp developers have "very clear No AI stances" and have disowned AI-made "slopcomps" that borrow their names (Kotaku). For players, the AI browser ports Kotaku tested fall into a murky middle. TDGN says that whether they use original assets, and on what basis, "the sources do not say" (TDGN).

4) Should you update your PS5 firmware?

Short answer: yes. Keep it updated.

What the versions are (per sources)

  • Up to 13.60 (July 2026): the range covered by the public Relapse exploit, according to Ars Technica (7.00–13.60 per specialist sites) (Ars Technica). Background is in yesterday's post.
  • 14.00 (16 Sep 2026): outside Relapse's range, per scene trackers (OneJailbreak).
  • 14.10 (26.06-14.10.00, 1 Oct 2026): Sony's notes say only "We've made some security fixes to the system software" and improved "performance and stability". It rolled out in phases (Push Square). Sony hasn't said 14.10 is a response to Relapse. That link is an inference. As of 12 Oct we found no newer release.

What updating gets you

  • Security fixes. That is the stated purpose of 14.10 (Push Square).
  • Games and apps that work. Sony's support page warns: "You might not be able to use some applications or content without first updating the system software on your console" (PlayStation Support). New games often need the latest system software.
  • PSN and online play. Sony tells owners to keep system software "always updated to the latest version" (PlayStation Support). RockstarINTEL reported Sony began requiring 14.00 for PSN after the PS4 GTA Online modder wave. That is the outlet's report, not a confirmed Sony statement.
  • Warranty protection. Sony warns that installing updates from other sources, or on a modified console, "can void the system warranty" (PlayStation Support).

What staying on old firmware means

  • Known, publicly documented security holes stay open on your console.
  • Over time you may be locked out of online play, PSN features and new releases, all of which expect current firmware.
  • Voxtly also warns that running unofficial software can put your PSN account at risk (Voxtly).

Recommendation: turn on automatic updates in the PS5's settings (Sony's guide), install only official updates from Sony, and don't run unofficial software on a console you use with your PSN account.

What we deliberately left out

  • How any decompilation, recompilation, AI-agent workflow or "clean room" setup is actually carried out (tools, prompts, build steps).
  • How to extract, dump or decrypt game files, BIOS or keys, and where to find ROMs, ISOs or prebuilt ports.
  • Links to download any port, browser port, emulator or ROM. GitHub's own DMCA notices are linked only as public legal records.
  • Any jailbreak, exploit or payload detail, and any advice on avoiding, blocking or delaying PS5 updates or "which firmware to stay on".

FAQ

Is it legal to make an AI-decompiled port of a game I own? No court has ruled on the 2026 AI wave. US case law protects some reverse engineering done to build original, compatible code. It doesn't protect redistributing a copyrighted game's code or assets. Recent publisher responses (Activision, Bethesda, Take-Two) were takedowns. Not legal advice.

Is it legal to play one? Downloading a port that bundles a game's original assets is downloading an unauthorised copy. "Bring your own files" projects are a grey area that rights holders have challenged at least once (Vice City, Dec 2025).

When will old games enter the public domain? Not for decades. Company-owned games are protected for 95 years from publication in the US and 70 years from publication in Korea, and their names can remain trademarks indefinitely.

Can a publisher own a game mechanic? Not through copyright. A patent can cover a specific technical method for about 20 years. Namco's loading-screen minigame patent ran out in 2015.

Should I update my PS5 to 14.10? Yes. It contains security fixes and keeps PSN and new games working.

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#reverse-engineering#decompilation#copyright#dmca#ai#take-two#nintendo#activision#bethesda#ps5#firmware#2026
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