It is perfectly legal and permissible to reverse engineer a system in order to demonstrate how it works. You can publish those findings, that is not illegal. Knowledge isn’t illegal, acts are illegal. 17 U.S. Code § 1201 specifies this very clearly - “to ‘circumvent a technological measure’ means to descramble a scrambled work, to decrypt an encrypted work, or otherwise to avoid, bypass, remove, deactivate, or impair a technological measure, without the authority of the copyright owner”. Yuzu developers aren’t doing that - the user is doing that.
The subsection also specifies that “No person shall manufacture, import, offer to the public, provide, or otherwise traffic in any technology, product, service, device, component, or part thereof” and lists three qualifiers:
- “primarily designed or produced for the purpose of circumventing a technological measure that effectively controls access to a work protected under this title” - that’s not what the emulator is primarily designed to do, it’s what it must do in order to fulfil its primary function, which is emulation
- “has only limited commercially significant purpose or use other than to circumvent a technological measure that effectively controls access to a work protected under this title” - that’s a second no, it has a large swathe of uses besides circumvention, even if we agree that it’s designed to circumvent measures at all
- “is marketed by that person or another acting in concert with that person with that person’s knowledge for use in circumventing a technological measure that effectively controls access to a work protected under this title” - this one’s tricky because while Yuzu isn’t actively marketed in this way, the developers had pretty loose lips and should’ve kept their mouths shut in regards to *how* one might obtain keys. That’s on them, but could he argued in court as documentation. It wasn’t, so we don’t know the outcome
Your analogy is silly, and let me explain to you why. I can purchase a car without an engine right now and I don’t need a driver’s license to do so. I can even build that car as a kit and nobody in their right mind will ask me to pay tax on it because it’s not a motor vehicle and *cannot function*. It only becomes a motor vehicle the moment I put an engine in it. I need to supply the engine, it’s the engine that’s relevant in the “motor vehicle” equation - fuel is a consumable. You could call ROM’s fuel, since that’s what an engine runs on. You should pay for your fuel, nobody suggests that you should steal fuel. What you’re suggesting is that the Yuzu team is somehow liable for selling cars without engines because they had working drivetrains. That’s silly. The wheels won’t spin until the user attaches an engine, and at that point it’s on the user to make sure that they comply with any and all regulation regarding motor vehicles.