Tesla Owner DIY HW4 Upgrade: Why Tesla Won't Do It

One Tesla owner has just completed a DIY Tesla HW4 upgrade on his 2022 Model 3, raising fresh questions about why the automaker insists the retrofit is too difficult. Michał Gapiński, a Poland-based tinkerer best known for the Tesla Android project, swapped his car's HW3 computer for the newer HW4 unit himself—and described the work as far lighter than Tesla suggests. The story, first reported by Electrek on August 18, 2026, has reignited a long-running debate over Tesla's Full Self-Driving hardware promises.

What is Tesla HW4 and why does it matter?

Tesla's Hardware 4, also called AI4, is the company's latest self-driving computer generation. Compared with HW3—introduced in 2019—HW4 offers significantly more processing power, higher-resolution cameras, and expanded memory. For owners who bought Full Self-Driving (FSD) packages years ago, HW4 represents the minimum hardware Tesla now says is needed for unsupervised autonomy. The problem? Millions of vehicles still run HW3, and Tesla has acknowledged that HW3 "simply does not have the capability" for the level of autonomy it marketed.

HW3 vs HW4 comparison

Inside the DIY HW3-to-HW4 retrofit

Gapiński's project offers a rare real-world test of Tesla's upgrade claims. According to the Electrek report, the swap required what he called "light ECU hacking," plus basic materials like epoxy and zip ties. "It's not as bad as it seemed," he said, adding that Tesla "could have done it ages ago." The retrofit was not entirely plug-and-play: Gapiński acknowledged the project was still incomplete and needed additional parts to restore full driving-video functionality. Still, the fact that an individual owner—not a Tesla service center—managed the core computer replacement challenges Tesla's official position that the process is too complex for widespread deployment.

The broader context is important. Tesla sold cars for years with the promise that they included "all hardware needed for Full Self-Driving." Since 2016, that commitment has evolved through HW1, HW2, HW2.5, and HW3. The Tesla Full Self-Driving timeline shows a pattern of hardware promises followed by later admissions that upgrades are required. Gapiński's DIY success now feeds a simple question: if one owner can do it in a garage, why can't Tesla?

Why Tesla says the upgrade is so hard

Tesla's official explanation is that a proper HW3-to-HW4 retrofit involves more than swapping the computer. The company says new cameras are also required because HW4 uses higher-resolution sensors with different connectors and mounting points. During an April 2026 earnings call, CEO Elon Musk proposed building urban "microfactories" to perform these swaps for roughly 4 million affected cars. Since then, Electrek notes, there has been no visible progress on that plan.

Musk has been blunt about the scope. In an earlier investor call, he said Tesla would have to upgrade HW3 cars for FSD buyers, calling it "painful and difficult." The Tesla HW3 retrofit cost could be substantial, and Tesla has not disclosed how many FSD purchases would qualify for a free or discounted upgrade. That uncertainty has fueled frustration among owners who paid thousands of dollars for FSD years ago.

Impact on Tesla owners and pending class actions

The DIY retrofit story lands at a delicate moment. Tesla faces small-claims cases and global class actions over FSD non-delivery. Owners argue that if Tesla cannot deliver the autonomy it sold, it should offer free hardware upgrades or FSD license transfers to new vehicles. The Tesla FSD class action lawsuit remains a key legal test of whether Tesla's marketing crossed from optimism into misrepresentation.

For now, Gapiński's project is more proof of concept than production solution. But it gives Tesla owners ammunition in a fight that has been simmering for years. "The hardware is available, the swap is doable," the report concludes, "so the real obstacle may be cost—and Tesla's willingness to absorb it."

FAQ: Tesla HW4 upgrade and Full Self-Driving

Can a Tesla owner upgrade from HW3 to HW4?

Yes, one owner demonstrated a partial DIY retrofit, but Tesla has not offered an official path for consumers. The process requires computer replacement and, according to Tesla, new cameras.

Why does Tesla say the HW4 upgrade is difficult?

Tesla says HW4 requires higher-resolution cameras and different mounting, making a full retrofit complex. Elon Musk has proposed microfactories, but no timeline has been delivered.

How many Tesla cars still use HW3?

Tesla estimates around 4 million vehicles are on HW3, though the exact number of FSD buyers is undisclosed.

Will Tesla offer a free HW4 upgrade for FSD owners?

Tesla has not committed to free upgrades. Class actions and small-claims cases are pressing the company to provide retrofits or license transfers.

What is the difference between HW3 and HW4?

HW4 has higher-resolution cameras, more processing power, and more memory, which Tesla says is necessary for unsupervised Full Self-Driving.