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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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Tesla removes Safety Monitors, begins fully autonomous Robotaxi testing
This development, in terms of the Robotaxi program, is massive. Tesla has been working incredibly hard to expand its fleet of Robotaxi vehicles to accommodate the considerable demand it has experienced for the platform.
Tesla has started Robotaxi testing in Austin, Texas, without any vehicle occupants, the company’s CEO Elon Musk confirmed on Sunday. Two Tesla Model Y Robotaxi units were spotted in Austin traveling on public roads with nobody in the car.
The testing phase begins just a week after Musk confirmed that Tesla would be removing Safety Monitors from its vehicles “within the next three weeks.” Tesla has been working to initiate driverless rides by the end of the year since the Robotaxi fleet was launched back in June.
Two units were spotted, with the first being seen from the side and clearly showing no human beings inside the cabin of the Model Y Robotaxi:
A Tesla without a driver was spotted traveling on public roads! pic.twitter.com/ZLbduf4cKa
— TESLARATI (@Teslarati) December 14, 2025
Another unit, which is the same color but was confirmed as a different vehicle, was spotted just a few moments later:
NEWS: A second Tesla Model Y Robotaxi running FSD Unsupervised has just been spotted driving itself on public roads in Austin, Texas, with no one in the front seats.
This is a different car from the one spotted earlier. They have different license plates.
h/t @Mandablorian https://t.co/5URYsUGyD0 pic.twitter.com/CIUi4mXi33
— Sawyer Merritt (@SawyerMerritt) December 14, 2025
The two units are traveling in the general vicinity of the South Congress and Dawson neighborhoods of downtown Austin. These are located on the southside of the city.
This development, in terms of the Robotaxi program, is massive. Tesla has been working incredibly hard to expand its fleet of Robotaxi vehicles to accommodate the considerable demand it has experienced for the platform.
However, the main focus of the Robotaxi program since its launch in the Summer was to remove Safety Monitors and initiate completely driverless rides. This effort is close to becoming a reality, and the efforts of the company are coming to fruition.
Testing is underway with no occupants in the car
— Elon Musk (@elonmusk) December 14, 2025
It is a drastic step in the company’s trek for self-driving technology, as it plans to expand it to passenger vehicles in the coming years. Tesla owners have plenty of experience with the Full Self-Driving suite, which is not fully autonomous, but is consistently ranked among the best-performing platforms in the world.
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Tesla refines Full Self-Driving, latest update impresses where it last came up short
We were able to go out and test it pretty extensively on Saturday, and the changes Tesla made from the previous version were incredibly impressive, especially considering it seemed to excel where it last came up short.
Tesla released Full Self-Driving v14.2.1.25 on Friday night to Early Access Program (EAP) members. It came as a surprise, as it was paired with the release of the Holiday Update.
We were able to go out and test it pretty extensively on Saturday, and the changes Tesla made from the previous version were incredibly impressive, especially considering it seemed to excel where it last came up short.
Tesla supplements Holiday Update by sneaking in new Full Self-Driving version
With Tesla Full Self-Driving v14.2.1, there were some serious regressions. Speed Profiles were overtinkered with, causing some modes to behave in a strange manner. Hurry Mode was the most evident, as it refused to go more than 10 MPH over the speed limit on freeways.
It would routinely hold up traffic at this speed, and flipping it into Mad Max mode was sort of over the top. Hurry is what I use most frequently, and it had become somewhat unusable with v14.2.1.
It seemed as if Speed Profiles should be more associated with both passing and lane-changing frequency. Capping speeds does not help as it can impede the flow of traffic. When FSD travels at the speed of other traffic, it is much more effective and less disruptive.
With v14.2.1.25, there were three noticeable changes that improved its performance significantly: Speed Profile refinements, lane change confidence, and Speed Limit recognition.
🚨 Many of you asked us to test highway driving with Tesla Full Self-Driving v14.2.1.25. Here’s what we noticed:
✅ Speed Profiles are significantly improved. Hurry Mode is no longer capped at 10 MPH over the speed limit, and now travels with the flow of traffic. This is much… pic.twitter.com/48ZCGbW0JO
— TESLARATI (@Teslarati) December 13, 2025
Speed Profile Refinement
Speed Profiles have been significantly improved. Hurry Mode is no longer capped at 10 MPH over the speed limit and now travels with the flow of traffic. This is much more comfortable during highway operation, and I was not required to intervene at any point.
With v14.2.1, I was sometimes assisting it with lane changes, and felt it was in the wrong place at the wrong time more frequently than ever before.
However, this was one of the best-performing FSD versions in recent memory, and I really did not have any complaints on the highway. Speed, maneuvering, lane switching, routing, and aggressiveness were all perfect.
Lane Changes
v14.2.1 had a tendency to be a little more timid when changing lanes, which was sort of frustrating at times. When the car decides to change lanes and turn on its signal, it needs to pull the trigger and change lanes.
It also changed lanes at extremely unnecessary times, which was a real frustration.
There were no issues today on v14.2.1.25; lane changes were super confident, executed at the correct time, and in the correct fashion. It made good decisions on when to get into the right lane when proceeding toward its exit.
It was one of the first times in a while that I did not feel as if I needed to nudge it to change lanes. I was very impressed.
Speed Limit Recognition
So, this is a complex issue. With v14.2.1, there were many times when it would see a Speed Limit sign that was not meant for the car (one catered for tractor trailers, for example) or even a route sign, and it would incorrectly adjust the speed. It did this on the highway several times, mistaking a Route 30 sign for a 30 MPH sign, then beginning to decelerate from 55 MPH to 30 MPH on the highway.
This required an intervention. I also had an issue leaving a drive-thru Christmas lights display, where the owners of the private property had a 15 MPH sign posted nearly every 200 yards for about a mile and a half.
The car identified it as a 55 MPH sign and sped up significantly. This caused an intervention, and I had to drive manually.
It seems like FSD v14.2.1.25 is now less reliant on the signage (maybe because it was incorrectly labeling it) and more reliant on map data or the behavior of nearby traffic.
A good example was on the highway today: despite the car reading that Route 30 sign and the Speed Limit sign on the center screen reading 30 MPH, the car did not decelerate. It continued at the same speed, but I’m not sure if that’s because of traffic or map data:
🚨 We listened to and read a lot of you who had a complaint of Tesla Full Self-Driving v14.2.1 incorrectly reading Speed Limit signs
This appears to be resolved in v14.2.1.25.
Here’s a breakdown: pic.twitter.com/TEP03xrMbt
— TESLARATI (@Teslarati) December 13, 2025
A Lone Complaint
Tesla has said future updates will include parking improvements, and I’m really anxious for them, because parking is not great. I’ve had some real issues with it over the past couple of months.
Today was no different:
🚨 My lone complaint with my drive on Tesla FSD v14.2.1.25 was this strange parking instance.
FSD swung out wide to the left to pull into this spot and this is where it seemed to be stumped. I gave it about 10 seconds after the car just stopped moving for it to make some… https://t.co/ZEkhTHOihG pic.twitter.com/TRemXu5DLf
— TESLARATI (@Teslarati) December 13, 2025
Full Self-Driving v14.2.1.25 is really a massive improvement over past versions, and it seems apparent that Tesla took its time with fixing the bugs, especially with highway operation on v14.2.1.
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Tesla hints at Starlink integration with recent patent
“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”
Tesla hinted at a potential Starlink internet terminal integration within its vehicles in a recent patent, which describes a vehicle roof assembly with integrated radio frequency (RF) transparency.
The patent, which is Pub. No U.S. 2025/0368267 describes a new vehicle roof that is made of RF-transparent polymer materials, allowing and “facilitating clear communication with external devices and satellites.”
Tesla believes that a new vehicle roof design, comprised of different materials than the standard metallic or glass elements used in cars today, would allow the company to integrate modern vehicular technologies, “particularly those requiring radio frequency transmission and reception.
Tesla has recently filed a US patent application on integrating RF transparent materials into the roof structure.
“facilitating clear communication with external devices and satellites”
Tesla fleet is getting @Starlink connectivity integration soon. LFG @Tesla @elonmusk… pic.twitter.com/bLa8YtPLd1
— Chansoo Byeon (@Chansoo) December 9, 2025
Instead of glass or metallic materials, Tesla says vehicles may benefit from high-strength polymer blends, such as Polycarbonate, Acrylonitrile Butadiene Styrene, or Acrylonitrile Styrene Acrylate.
These materials still provide ideal strength metrics for crashworthiness, stiffness for noise, vibration, and harshness control, and are compliant with head impact regulations.
They would also enable better performance with modern technologies, like internet terminals, which need an uninterrupted signal to satellites for maximum reception. Tesla writes in the patent:
“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”

One of the challenges Tesla seems to be aware of with this type of roof design is the fact that it will still have to enable safety and keep that at the forefront of the design. As you can see in the illustration above, Tesla plans to use four layers to increase safety and rigidity, while also combating noise and vibration.
It notes in the patent that disclosed examples still meet the safety requirements outlined in the Federal Motor Vehicle Safety Standards (FMVSS).
Starlink integrated directly into Tesla vehicles would be a considerable advantage for owners. It would come with a handful of distinct advantages.
Initially, the inclusion of Starlink would completely eliminate cellular dead zones, something that is an issue, especially in rural areas. Starlink would provide connectivity in these remote regions and would ensure uninterrupted service during road trips and off-grid adventures.
It could also be a critical addition for Robotaxi, as it is crucial to have solid and reliable connectivity for remote monitoring and fleet management.
Starlink’s growing constellation, thanks to SpaceX’s routine and frequent launch schedule, will provide secure, stable, and reliable internet connectivity for Tesla vehicles.
Although many owners have already mounted Starlink Mini dishes under their glass roofs for a similar experience, it may be integrated directly into Teslas in the coming years, either as an upgrade or a standard feature.