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The Tesla MCU1 conundrum: How early FSD adopters were left behind in limbo
When Tesla started selling Full Self-Driving back in 2016, the company was in a far different place than where it is today. Back then, Tesla was not the most valuable carmaker by market cap, nor was it a tried and tested business that no longer needs credits to become profitable on a quarterly basis. Back then, believing in Tesla and its promises for innovative tech was not something that was done lightly.
Back then, it took a leap of faith.
And that was exactly what a number of Tesla Model S and Model X owners did. With Elon Musk and Tesla noting that every vehicle produced at the time had the necessary hardware to achieve autonomous driving, a good number of Model S and Model X owners decided to go all-in on the promise that achieving self-driving was just a matter of software. And if it turns out that it wasn’t, Tesla would ensure that early adopters would get the hardware necessary to make their vehicles on par with the company’s newer, more advanced cars.
This promise has not been granted by Tesla — at least not fully — and a good number of early FSD adopters, who were the first to put their faith in the company and its autonomous driving program, have now found themselves in a limbo of sorts. A limbo that now involves an aging vehicle, a fully paid Full Self-Driving suite, and what is starting to seem like a path to FSD that is blocked by the company’s old MCU1 unit, which happens to be linked to a recall of about 130,000 Model S and Model X earlier this year.
An FSD Limbo
The Tesla Model S and Model X were still fitted with MCU1 units when the company started selling FSD. By this time, Tesla’s reputation as a producer of the best electric vehicles in the market was already established. It was then no surprise that when the company debuted its first FSD demo in 2016, numerous Model S and Model X owners were all too willing to support Tesla.
“I bought my Model S in 2017 based on their advertising claiming that it had the necessary hardware for self-driving. Tesla advertised that I would get true L5 autonomy. (The ad) also stated ‘The person in the driver’s seat is only there for legal reasons. He is not doing anything. The car is driving itself,’” a longtime Tesla owner told Teslarati in a statement. The Model S owner added that he initially purchased Enhanced Autopilot for $5,000, but he later bought FSD for an additional $5,000 last year when Elon Musk noted that he was confident that complete autonomy was on hand.
Tesla is a company built on rapid innovation. Over the years, Tesla has gained a reputation as a carmaker that rolls out improvements as soon as they are available. Unlike traditional automakers that typically wait a year before introducing minor updates to their vehicles, Tesla improves its electric cars through over-the-air software updates. But Tesla had also implemented hardware changes in the past, such as when the company started the rollout of its MCU2 units in March 2018. The company also updated its Autopilot computer from Hardware 2.0 to Hardware 2.5, and later, to Hardware 3.0.
Elon Musk, for his part, has assured FSD buyers that their vehicles would have the necessary hardware when Tesla achieves full autonomy. And to some degree, Musk has stayed true to his word. Owners of older vehicles that purchased FSD were provided a free upgrade to Hardware 3.0. Tesla, however, has introduced its MCU1 to MCU2 retrofit as a paid upgrade. Quite unsurprisingly, some early FSD adopters opted out of the optional infotainment system update. This has proven to be problematic.
Apparent MCU1 Limitations
As Tesla started rolling out more advanced features, vehicles equipped with MCU1 units started getting left out of key functions like Sentry Mode and Tesla Theater. Enhanced driving visualizations were also available only on vehicles that were fitted with MCU2 units. It was over this period that early FSD adopters found themselves steadily getting left behind. New features would be introduced, but they would be focused on MCU2 cars. Software updates were frequently rolled out to the fleet, but not for MCU1 vehicles. This was highlighted by a Tesla Model S 75 owner who purchased FSD, and who shared a photo with Teslarati showing that his vehicle is still running 2020 firmware despite the car stating that its software was up to date.
The Model S 75 owner’s experience is not unique. Over the course of this article’s research, Teslarati has received similar stories from early FSD adopters. A longtime electric vehicle advocate who purchased a Model S 100D with Enhanced Autopilot and Full Self-Driving described his current ownership experience as similar to having a device that is no longer supported.
“In the recent past, I have not even had 2021 firmware update as if my car is already unsupported before all the features promised are delivered. I was hoping to get FSD Beta, but that feature has not been demonstrated for my configuration by anyone, so far and no communication from Tesla on exactly when we can expect our car to participate in this to provide feedback,” the Model S 100D owner wrote.
While Tesla may be quite silent on whether its older MCU1 units are indeed the culprit behind the less-than-stellar ownership experience of FSD’s early adopters, those who have owned multiple Teslas over the years have all but confirmed that the aging component seems to be a key issue. One Tesla owner who shared his story with Teslarati noted that his 2017 Model S — which has FSD and whose infotainment system was upgraded to MCU2 — received the “Request FSD Beta” button just fine, but his 2017 Model X — which is still equipped with an MCU1 unit — did not receive anything at all despite having FSD.
“Now the beta button is finally coming. All the early adopters that paid for FSD were eager to get it. Most people had their computers upgraded by now to the FSD version and were told that is all they needed; it would work fine on MCU1. So the excitement for everyone grew, especially those that had waited the longest. After several delays, the button came. My Model S got the button right away, but it never came for the Model X with MCU1. There was no communication from Tesla at all. No email sent out in advance. All of those people found out through the disappointment of not getting it. Then searching through chat groups, (I discovered) that no one with MCU1 got it. Why can’t Tesla show some respect for these customers and at least communicate in advance?” the veteran Tesla owner told Teslarati.
Transparency and Understanding
One prevalent theme among the early FSD adopters who contacted Teslarati with their stories was the lack of communication on Tesla’s part. This is something that has been reported by longtime Tesla owners for some time now. And while it is understandable that Tesla is juggling a lot of balls in the air as it expands its business to other countries and other segments, having a responsive communications team, or at least investing some of its funds into the creation of one, would definitely not hurt.
Tesla owners, particularly early FSD adopters, are more than willing to be understanding of the company’s plight and challenges, after all. In this sense, Tesla would probably be better off behaving more like a company that truly cares for its customers and less like a traditional automaker that is just looking for the next sale.
Unfortunately, this is something that became a reality for Tesla FSD adopters who purchased vehicles just before March 2018, when the company transitioned its vehicles to MCU2 units. As per a Tesla Model S 75D owner, his order initially had a March 2018 delivery date, but he was encouraged by the company to take an early delivery instead. As a result, he has missed out on numerous features, and he is yet to enjoy some key FSD capabilities that the company has been rolling out as of late.
“I have a December 2017 Model S 75D. I had placed an order for it in mid-December with a delivery date of March 2018. Tesla reached out to me just before the end of the year with a vehicle that someone canceled their order on. If I had known that March 2018 vehicles and not December 2017 vehicles would have MCU2, I would have never accepted the other car. I feel like they misled me on my order.
“I told myself I was okay with it because my original order stated it would be fully capable of FSD. Unfortunately, as years passed, MCU2 vehicles had plenty of extra features, and figured I would eventually get my FSD capabilities anyways. Unfortunately, I am now seeing Model 3, Model Y, and Model S vehicles with orders placed years after me getting capabilities I should have received. Now they are getting FSD Beta, and I am left wondering if I will ever get it with MCU1. I do not wish to spend money on the MCU2 upgrade as they said my vehicle was already capable,” the Model S 75D owner wrote.
What Elon Musk is Pledging Now
Elon Musk has been made aware of the issue surrounding FSD’s early adopters, and most recently, the CEO noted that early production vehicles would require some camera upgrades to get full access to the FSD Beta. Musk noted that the new cameras, just like HW3.0, were included in Full Self-Driving’s price so retrofits are all but assured. Yet even in the CEO’s recent statements, a reference to the complications that are seemingly caused by the company’s aging MCU1 units was absent.
Years ago, these Tesla owners put their faith in Elon Musk and his vision to achieve Full Self-Driving. And they were given a word. This promise has been met to some degree, but not fully. Details such as the absence of MCU2 units are severely hobbling the experience of Tesla owners that quite literally helped fund the development of Tesla’s growth into a mass market manufacturer and a key player in the autonomous driving sphere. And until the company decides to do something for its early FSD adopters, Tesla would continue to have some of its most loyal customers be subjected to a substandard ownership experience.
Early Model S and Model X owners are a small fraction of Tesla’s fleet at this point. The number of owners who purchased FSD and are still stuck with MCU1 units is even smaller. The costs to upgrade these owners’ cars would undoubtedly be substantial, but they would likely be marginal for Tesla in the long run, especially with the way the company has been growing year-over-year. Perhaps Tesla could provide complimentary MCU2 retrofits to early FSD buyers when they get their cameras upgraded for free. By doing so, Elon Musk could prove that he is a man of his own word.
Musk himself said it, after all. He may be late, but he pulls through. Now it’s time to stand by these words. With the rollout of the FSD Beta, Full Self-Driving is closer than ever. Tesla just has to pull through for a group of owners who took that leap of faith when the company announced its intentions to develop a self-driving system.
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Elon Musk
Elon Musk rips ABC News over fatal NYC Tesla crash report
Musk pushed back on NYC Tesla crash coverage, pointing to a pattern of premature blame.
Elon Musk pushed back overnight against media framing of a fatal Tesla crash in Midtown Manhattan, telling a user on X that “it wasn’t the car” and that the vehicle’s Autopilot system had nothing to do with the wreck.
The crash happened just before 3 a.m. Wednesday, when a 2024 Tesla Model Y struck a sidewalk shed outside 315 Madison Ave., a bus stop pole and a mailbox on East 42nd Street, according to the NYPD. The car kept moving several more blocks before stopping near Second Avenue. Both women inside, each 27, were taken to Bellevue Hospital, where the passenger was pronounced dead. The driver was charged with vehicular manslaughter, driving while ability impaired and leaving the scene of an accident.
Police have not attributed the crash to Autopilot or Full Self-Driving in any public statement. The charges point to impairment, not software. Musk’s response followed a since-deleted ABC News post that he said mischaracterized the incident. Replying to a user on X, Musk wrote that if Autopilot had been engaged, “they would not have crashed,” and added that “the legacy media will never forgive Tesla for failing to advertise with them,”
The legacy media will never forgive Tesla for failing to advertise with them
— Elon Musk (@elonmusk) September 9, 2026
It’s a familiar cycle for Tesla. In June, headlines from several national outlets described a fatal crash in Katy, Texas, as happening while the car was “on autopilot,” based on the driver’s own account to police after his Model 3 struck a home and killed a 76-year-old woman. Tesla’s data told a different story when Ashok Elluswamy, Tesla’s head of AI, said the driver had pressed the accelerator to 100% and reached 73 mph in a residential zone. Harris County prosecutors later confirmed the human override and the driver was charged with manslaughter.
Florida Gov. Ron DeSantis pointed to that same Katy crash last month to argue that outlets routinely name Tesla in crash headlines while leaving other automakers unnamed, even after a driver’s own actions are shown to be the cause. A similar pattern played out in 2024, when Musk had to clarify that FSD was never even downloaded onto the Model 3 involved in a fatal Colorado DUI crash, despite a passenger’s claim that an “auto drive feature” was in use.
Tesla has not issued a separate statement on the Manhattan crash beyond Musk’s posts on X. The NYPD’s investigation is ongoing, and no cause for the driver losing control has been released.
Tesla’s two recently-defunct flagship models, the Model S and Model X, are getting a big upgrade, according to the company’s Head of AI, Ashok Elluswamy.
Older Hardware 3 Model S and Model X vehicles have been the last major holdouts in Tesla’s Full Self-Driving v14 Lite rollout, and that wait now appears to be ending.
Tesla brings closure to flagship ‘sentimental’ models, Musk confirms
At Tesla’s Cybercab launch, AI chief Ashok Elluswamy told Ryan McCaffrey that he thought the S and X build “was supposed to go out last week.” Evidently, Elluswamy expects the suite to be rolled out to those HW3 Model S and Model X very soon:
For my @Tesla friends – and specifically Model S & X owners with HW3 who are waiting on FSD v14 Lite – I spoke to @aelluswamy at the Cybercab launch, & when I asked for an ETA on v14 Lite for S/X owners, he said, “Oh, I thought it was supposed to go out last week.”
So: soon! 🙌
— Ryan McCaffrey (@DMC_Ryan) September 7, 2026
Those cars are not the current Model S and Model X, which already ship with Hardware 4. They are the pre-refresh flagships built around Tesla’s older Autopilot computer, often called HW3 or AI3.
Tesla stopped putting that computer in new vehicles years ago, which is why owners treat these S and X cars as a closed generation. Model 3 and Model Y vehicles on the same computer began receiving v14 Lite in late June 2026 and saw a wider North American expansion in July. South Korea followed as an early international market. The S and X versions of the same software never joined that wave.
v14 Lite is Tesla’s way of squeezing the current v14 driving stack onto hardware that cannot run the full AI 4 model. The company describes the process as distillation: behaviors learned on the newer computer, including reinforcement learning and offline models, are compressed so the older chip and cameras can use them as a guide.
Early descriptions put the distilled network at roughly 15 percent of the original size. The result is still supervised Level 2 driving. Tesla has been clear that HW3 cannot support unsupervised Full Self-Driving or robotaxi operation because of memory and bandwidth limits.
The feature list is what made the wait so frustrating for S and X owners, as plenty of new features are to be shipped with it.
Official notes for the first Lite build, firmware 2026.20.5.1, added parking, unparking, and reversing; arrival options for a parking lot, street, driveway, or curbside; speed profiles that stay available at all times; and start-from-park engagement. Tesla also claimed better handling of merges, forks, pedestrians, traffic lights, and cut-ins, plus fewer false slowdowns and smoother lane centering.
A mid-July follow-on build, 2026.20.6.10, added more of the Hardware 4 interface, including a standalone Self-Driving app and the ability to start a trip from Park without a brake-pedal confirmation.
Elluswamy called that version the one “likely going to wide release.”
That wide release already reached most other HW3 cars in the United States and Canada. International timing still depends on regional validation and regulatory approval. For S and X owners, the remaining work appears to be model-specific validation rather than a new software stack.
There is no official Tesla changelog or build number for those two models yet, only Elluswamy’s offhand timeline. Some HW3 drivers who already have Lite report large gains over v12.6; others have described new indecision or phantom braking. The next test will be whether the same software lands cleanly on the older flagships that have waited the longest.
Yesterday, we reported on Tesla Cybertruck getting some major adjustments from a manufacturing standpoint in an effort to make the all-electric pickup more cost-effective, more reliable, more serviceable, and more easily produced.
Tesla Cybertruck engineer reveals new changes in ‘constantly evolving’ pickup
One of those changes was the addition of a self-reinforcing polypropylene aero shield that sits underneath the truck. Previously, Tesla utilized aluminum for this, but the self-reinforcing polypropylene was more durable while also being cheaper and lighter.
Tesla has revealed another small change it made to the Cybertruck, and it has to do with the side repeater cameras.
Tesla does not wait for a new model year to improve its vehicles. On September 8, Cybertruck lead engineer Wes Morrill posted side-by-side photos of an updated side repeater camera housing now rolling off the line at Gigafactory Texas.
The triangular camera pod mounted on the front fender looks almost identical at first glance. A closer look reveals a revised contour that uses the air already flowing around the truck to keep the lens clearer in rain and road spray.
The side repeater camera was updated – the version on the left is the newer part which uses passive geometry to create airflow disturbance that better keep water off the lens while driving. No cost penalty, just pure vision improvement. pic.twitter.com/wAbXtcL1Jf
— Wes (@wmorrill3) September 8, 2026
The side repeater cameras sit in an exposed position on the Cybertruck’s angular stainless-steel body.
In wet weather, they readily collect water droplets that can degrade the image Autopilot and Full Self-Driving use for lane changes and blind-spot monitoring. Early production trucks sometimes left owners wiping lenses by hand or accepting temporary restrictions on driver-assistance features.
Tesla has added washers to cameras on certain other models and on Cybercab prototypes, but those active systems add cost, complexity, and extra potential leak points.
The new housing solves the problem with passive geometry. Subtle changes in the surround create localized airflow disturbances as the vehicle moves. Those eddies physically push water droplets away from the optical surface. Morrill called the result “pure vision improvement” achieved at “no cost penalty.” Once the production mold is updated, every subsequent part costs the same as the original.
The advantages compound quickly. Clearer cameras in rain improve the reliability of driver-assistance features precisely when they are needed most. The design consumes no extra energy and introduces no new failure modes.
New Cybertrucks built after the tooling changeover receive the updated part automatically. Some owners of trucks delivered as late as June 2026 have already confirmed they received the revised housing. Retrofit questions have appeared in replies, and the cameras appear electrically compatible, though Tesla has not announced an official service program.
A few millimeters of reshaped housing will not make headlines the way a new battery pack does, but these changes are incremental and increase the Cybertruck’s effectiveness as a vehicle over time.
This improvement illustrates how Tesla continues to refine the Cybertruck after volume production began. Better wet-weather vision, zero added cost, and no extra hardware add up to a meaningful gain in everyday usability and safety.
Elon Musk rips ABC News over fatal NYC Tesla crash report
Tesla’s two defunct flagship models are getting a big upgrade
