Autonomous driving company Comma.ai announced via its Twitter feed this morning that it would be canceling its forthcoming Comma One product. Comma One was supposed to bring after-market autonomy to third-party vehicles. The company was founded by hacker George Hotz (aka Geohot), who is credited as the first person to hack the iPhone. In his tweets under the Comma.ai account, Hotz said that he decided to discontinue production after he received a stern letter from the National Highway Traffic Safety Administration (NHTSA) requesting more information about how the product works and safety precautions built into the technology.

“First time I hear from them and they open with threats. No attempt at a dialog,” Hotz tweeted with a link to the NHTSA’s 10-page letter. “Would much rather spend my life building amazing tech than dealing with regulators and lawyers. It isn't worth it,” he added.

Finally, Hotz tweeted, “The comma one is cancelled. comma.ai will be exploring other products and markets. Hello from Shenzhen, China.”

A few hours later Hotz tweeted that the NHTSA “never asked for a test drive.”

The founder started Comma.ai in late 2015 after equipping his own Acura ILX with a homespun hardware and software system that allowed him to drive autonomously on freeways around the Bay Area. Tesla at the time offered Hotz a job, but he turned the job down, citing Tesla’s partnership with Mobileye. Hotz said he wanted to “crush Mobileye,” and when Tesla and Mobileye acrimoniously ended their partnership earlier this year, Hotz told Ars that “Mobileye doesn't want to innovate. Their business model is to work with regulators to lower the star safety ratings of cars that don’t have Mobileye in them, in order to force auto manufacturers to buy their chips.”

Working with regulators is apparently not Hotz’s style, but Ars e-mailed him to see if he had believed he could sell his product without ever interacting with regulators. We have not yet received a response. In fairness, it was 1am in Shenzhen, China, so we may well receive a response later today. If we do, we’ll update this article.

Still, the NHTSA letter seems to simply request details about the Comma One project that all autonomous vehicle manufacturers will likely have to provide under the agency’s new federal guidelines, published in September. So throwing out a product because a regulator has demanded more information on that product seems troublesome at best.

The NHTSA’s letter notes that the regulator had concerns about Comma One’s safety. “We are concerned that your product would put the safety of your customers and other road users at risk,” the letter notes in bold text. “We strongly encourage you to delay selling or deploying your product on the public roadways unless or until you can ensure it is safe.” The letter included a list of several questions about the functionality of the Comma One system, and it requested Comma.ai respond to the inquiries by November 10, 2016 or face civil penalties of up to $21,000 per day.

The information requests include items like “Describe in detail how the Comma One is installed in a vehicle and provide a copy of installation instructions for Comma One” as well as a request for the company to describe in detail the types of roadways and geographic areas in which the system can operate, as well as the speed, traffic, and weather conditions that might limit the system. The NHTSA also asks Comma.ai to describe any emergency shutoff features that the system might have and to describe any ways in which the system’s operation might infringe on the normal operation of the third-party vehicle.

Ars contacted the NHTSA, and a spokesperson noted, “We had concerns about reports regarding the safety of the comma.ai product and sent a request to the company for more information about how the product was installed and operated. Mr. Hotz’s decision to cancel the product is his own.”