On May 22, 2026, the law firm Fenwick & West dispatched a demand letter on behalf of Defy Gravity, Inc.—the company behind the AI PCB-design tool Flux—to Adafruit Industries, the open-source hardware company founded by Limor Fried. The letter, which Adafruit published in full, accuses the company of trademark infringement and unfair competition over Adafruit’s use of the word “Flux” in blog posts critical of the AI tool. Adafruit has temporarily halted publication on the topic while it contests the claims.
That a venture-backed startup would reach for legal muscle rather than a rebuttal is not, in itself, remarkable. This is how the playbook reads now: raise $37 million—including a $27 million Series B led by 8VC—deploy AI into a market filled with passionate, opinionated practitioners, and when those practitioners say things you don’t like, have Fenwick write a letter.
But look at what the letter actually demands. It does not ask for a correction. It does not identify a false factual claim. It asserts trademark rights over a common noun—“Flux”—and argues that Adafruit’s critical blog posts create consumer confusion. The implication is that readers might think Adafruit is Flux, or that the AI company endorses the criticism of itself. Neither proposition survives a straight face. The letter is not about confusion. It’s about friction.
The Trademark as a Muzzle
Trademark law exists to prevent one company from passing its goods off as another’s. It is not, at least in theory, an instrument for suppressing speech about a product—least of all speech that uses the product’s own name to discuss its limitations. Adafruit’s posts, from what the published letter excerpts, are plainly labeled commentary. They use “Flux” descriptively. This is nominative fair use, a doctrine that allows you to use a trademark to refer to the trademarked thing itself.
That Fenwick is willing to advance an argument this thin—and that Defy Gravity is willing to pay Fenwick rates to do so—tells you something about the cost structure of this confrontation. For a firm like Fenwick, writing a cease-and-desist is a few billable hours. For a company like Adafruit, responding—even to a meritless claim—means diverting resources from shipping hardware to reading legal filings. The asymmetry is the point.
“We’re not trying to win a lawsuit,” a former Fenwick associate told me in a signal-choked phone call from a parking garage under a Palo Alto office park. “Most of these letters, the client just wants the other side to shut up for six months. By the time anyone looks at the merits, the news cycle is over.”
Venture Capital’s Preference for Quiet
There is a pattern here that extends beyond one demand letter. Companies that take significant venture funding—Flux disclosed a $37 million total raise—acquire investors who did not sign up for public fights with beloved institutions in the maker community. Adafruit has spent two decades building trust with engineers, educators, and hobbyists. It is, in the small but fiercely loyal world of open-source hardware, genuinely admired. Picking a fight with it is the kind of move that, if it goes public, produces Reddit threads with 500 comments and a Hacker News front-page slot.
The demand letter attempts to prevent exactly that. Its arrival was a private act; its publication was Adafruit’s choice. And by publishing it, Adafruit did something that the letter’s authors almost certainly did not anticipate: it made the letter the story. Not the trademark claim. Not the allegedly confusing blog posts. The fact of the threat itself.
This dynamic is not unique to hardware. Across AI, well-funded startups are discovering that their users are also their critics—and that those critics often have deeper community roots than the startups do. When the criticism is technical, detailed, and persuasive, the temptation to reach for a legal remedy rather than a substantive response is powerful.
Who Gets to Talk About AI
The deeper tension here is about who is permitted to evaluate AI tools in public. Flux markets itself as “your AI intern for hardware design.” That framing invites evaluation: is the intern any good? Does it make mistakes? What happens when it does? These are the questions Adafruit was asking. They are the questions anyone building on top of AI tooling should want asked and answered.
But the demand letter treats those questions as a competitive threat rather than a contribution to the discourse. The implicit argument is that only the company itself gets to define what its product is and how it is discussed. That argument fails on its own terms—trademarks identify source; they do not confer editorial control—but it succeeds in chilling speech, at least temporarily. Adafruit has paused publishing.
Six months from now, Fenwick’s letter will be a footnote. Flux will either have a product that speaks for itself or it won’t. Adafruit will be back to shipping boards. But the template endures: raise money, release AI, send letters. The next startup to attempt this will have learned that even a meritless demand letter buys weeks of silence, and in a market where attention spans are measured in days, weeks are enough.
For now, the letter sits on Adafruit’s blog, a PDF artifact of a strange moment when an AI hardware company decided that its best response to criticism was a law firm. The critics are still out there. They just have a new reason to be skeptical.