We get our first view at hardware 4.0 for the Model Y
Greentheonly/Twitter
In a recent series of fascinating tweets, @greentheonly provided an unprecedented look into the internals of Tesla's new Model Y Hardware 4 or HW4. With his expertise and knowledge, Green shared detailed observations on the HW4's physical structure, board components, and the viability of retrofitting older models, giving the Tesla community much to ponder.
Breaking Down the HW4's Structure
Green's exploration of the HW4's complexities commenced with him acknowledging an "anonymous donor" for providing a chance to look inside Model Y's HW4. The serial numbers and other identifiers were blacked out. Green stated it was done to protect the donor after previous experiences, "Tesla is vengeful like this and went after the guy that did hw2.0 teardown by trying to deny warranty on unrelated repairs. Does not help that this new computer now has a (borderline illegal) 'warranty void if removed' sticker."
Delving into HW4's Core: Circuitry and Components
First up on the dissection table was the computer's physical form factor. According to Green, the HW4's form factor mirrors those of the S/X models, putting to bed any speculation around a potential retrofit to HW3 cars.
Moving deeper into the HW4, Green revealed that the board layout is similar to the HW4 on the Model S. However, as Green termed it, specific components, including the GPU and superior sound hardware, are now missing or depopulated. The use of cheaper non-Error-Correcting Code ram (ECC RAM) also seems to be a cost-cutting measure implemented by Tesla in this version of HW4 on the infotainment system side. Interestingly, this version of HW4 features two additional but depopulated display connectors, hinting at possible a possible second display in the vehicle.
Other distinguishing attributes of HW4 include a reoriented BroadR-Reach ethernet and the addition of a third, depopulated ethernet. Moreover, Green pointed out that the gateway chip has changed, too, with a different model from another vendor now in use. This chip, which was only seen in Chinese-made boards previously, seems to be a standard feature in all Model Y HW4 boards now.
Retrofitting HW3 to HW4: More Than Meets the Eye
The idea of retrofitting HW3 cars with HW4 stirred up quite a debate. According to Green, the concept may sound enticing, but it's not as straightforward as it seems. Modifying the vehicle to accommodate the new coolant pipe locations would be necessary for a retrofit, likely making this option more costly than simply manufacturing a new board in the old form factor.
Uncovering the Hidden Changes
Apart from the apparent changes, Green shared insights into some of the subtle modifications made by Tesla. For instance, the Texas-manufactured Model Ys feature a plastic "firewall" requiring a change in mounting methods for the new HW4. Despite the internal components remaining the same, the different mounting technique necessitates a unique part number for the computer.
The missing camera connectors were for additional cameras, such as a front bumper camera. However, as Green says, the absence of a connector doesn't mean that Tesla won't add them in the future. In fact, if Tesla had no intentions of adding such features, they wouldn't be available on the board at all, instead of just being unpopulated.
Implications for Current and Prospective Tesla Owners
For existing and future Tesla owners, these findings offer a clearer understanding of what to expect from the HW4-equipped Model Ys. Notably, questions still linger about additional cameras and if and when newer models will receive them. The Cybertruck prototype already has a front bumper camera, so it may only be a matter of time.
While it seems that retrofitting HW3 to HW4 may not be feasible due to the cost and complexity involved, Green isn't entirely ruling out the possibility. He believes a different version could theoretically be created for retrofits, although it's unlikely.
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Tesla’s Dan W Priestley attended the Advanced Clean Transportation (ACT) Expo in Anaheim, California, and provided an update on Tesla’s Semi truck program. The presentation covered several key developments on the status of Tesla’s Nevada Semi Factory, refinements to the Semi, and Tesla’s plans for charging and ramping production through 2026.
Let’s dig in and take a look at everything that was captured by the Out of Spec team at ACT Expo. The original video is embedded below if you’d like to watch it.
Semi Factory & Production Ramp
Priestley reaffirmed the timelines mentioned during Tesla’s Q4 2024 Earnings Call that Tesla will scale Semi production in 2026. To achieve this, Tesla has been actively building and expanding the Gigafactory Nevada site, specifically to support the production of the Tesla Semi. The dedicated Semi facility will have a targeted annual capacity of 50,000 Semi trucks.
Following the beginning of production, Tesla will utilize the initial trucks to integrate into its own logistics operations. This will serve as both a final real-world testing ground as well as an opportunity for Tesla to gather data internally. Tesla plans to begin subsequent customer deliveries throughout 2026 as the ramp-up continues.
Reuters also reported that Tesla is hiring over 1,000 new employees at the Semi Factory to begin the rapid ramping of the program.
Semi has already amassed 7.9 million miles with Tesla’s current testing and operational fleets, providing some real-world data and testing. Feedback for the truck has been exceptionally successful, with many drivers praising the Semi’s performance and comfort.
New Tesla Semi Features
Of course, it wouldn’t be a Tesla keynote without showing off some new things. The Semi will be available in 500-mile and 300-mile range configurations, now featuring updated mirror designs and a drop-down glass section to improve visibility and allow easier interaction with external elements—such as control panels at ports, for example.
New Electric Power Take-Off (e-PTO)
The Tesla Semi will also feature a new capability called Electric Power Take-Off, or e-PTO system. Similar to the PTO systems found on other vehicles, this will allow the Semi’s high-voltage battery to power auxiliary equipment at variable voltages. That includes being able to power things like climate-controlled reefer trailers, potentially replacing the noisy and polluting diesel generators traditionally used for this purpose.
Charging and Batteries
Out of Spec BITS/YouTube
Tesla is also working on an updated battery pack design for the final production design of the Semi. This new pack is designed to be more cost-effective to manufacture. The battery pack itself is slightly smaller than before, but the truck maintains the same level of range through efficiencies. Dan also confirmed during his keynote that the battery cells for the Semi will be sourced domestically inside the United States, helping to alleviate potential burdens due to tariffs.
On the charging front, Tesla is using MCS - the Megawatt Charging System - capable of 1.2MW - and designed specifically for Semi. The system uses the same V4 charging hardware found at Supercharger sites but focuses on that larger power output. Alongside a smaller physical footprint, Tesla will be able to configure these V4 cabinets for either dedicated Semi charging or for shared power scenarios with regular Superchargers. Tesla is also working on an integrated overnight charging product, but Tesla isn’t ready to talk about it yet.
46 Semi Charger Sites Coming
The 46 new MCS sites coming soon.
Out of Spec BITS/YouTube
Finally, Tesla has made substantial investments in a public charging network for the Semi. There are currently 46 sites in progress throughout the United States, and plans for significant expansion throughout 2026 and 2027. These sites are strategically located alongside major truck routes and within industrial areas to support long-haul and regional operations. Tesla is aiming to offer the lowest possible energy costs to operators to help incentivize adoption.
This was one of the best updates to the Tesla Semi we’ve received since its initial unveiling. It seems that the Semi will receive a big portion of Tesla’s attention in 2026, while Robotaxi and FSD Unsupervised take the stage this year.
The Tesla Semi has the potential to transform transportation even more dramatically than EVs already have, serving as a testament to Tesla’s mission to electrify the world.
Sentry Mode is an invaluable tool for owners - capable of keeping the vehicle safe and secure even when you’re not around. This is especially true in recent times, with the misguided and unfortunate incidents surrounding Tesla ownership, including damage to Tesla vehicles, showrooms, and Superchargers.
B-pillar Camera Recording and Dashcam Viewer
With the 2025 Spring Update on 2025.14, Tesla is expanding Sentry Mode’s functionality for certain vehicles with some much-needed changes. Sentry Mode and Dashcam can now record footage from the vehicle’s B-pillar cameras. These cameras are located on the side pillars of the vehicle, between the front and rear doors.
This adds two crucially needed viewpoints, making Tesla’s Sentry Mode a truly 360-degree security system. These cameras also provide the best angles for capturing license plates when parked, so they will be greatly appreciated by owners in the event of an incident.
These vehicles are also receiving an improved Dashcam Viewer, which now displays the six camera feeds along the bottom and a new grid view. It also allows users to jump back or forward in the video in 15-second increments.
However, to the disappointment of many owners, not all vehicles are receiving these updates due to the additional processing power needed.
Limited to Hardware 4 Vehicles, Ryzen Isn’t Enough
We have confirmed that Tesla is only adding the additional camera recording and improved Dashcam Viewer on hardware 4 (HW4 / AI4) vehicles. The newer hardware presumably has the additional processing power and bandwidth needed to handle recording and saving the two additional video streams during Sentry Mode and Dashcam.
For the time being, owners of HW3 vehicles are not receiving this feature. This includes all vehicles with HW3, even those with AMD Ryzen infotainment systems. If you’re not sure whether your vehicle has HW3 or HW4, you can refer to our FSD hardware guide.
While there’s no doubt that recording two additional camera streams would be more computationally intensive, we hope that Tesla adds the improved Dashcam Viewer to HW3 vehicles in a future update.
Cybertruck Also Missing Improved Sentry Mode
Surprisingly, and most confusing for many - is the fact that the Cybertruck is also not receiving the improved Dashcam Viewer and B-pillar camera recording with this update. This struck us as odd, especially since the Cybertruck is currently the only vehicle with the improved, more efficient version of Sentry Mode.
Every Cybertruck is equipped with HW4 and AMD Ryzen infotainment units, so this clearly isn’t a hardware restriction. It’s possible the more efficient Sentry Mode is playing a role here due to the infrastructure changes. However, we expect Tesla to address this in a future update and eventually release these features for the Cybertruck as well.
Given the Cybertruck’s high visibility and its status as a frequent target for both positive and negative attention, many owners hoped that the Cybertruck would be one of the vehicles to receive this feature.
Adaptive Headlights
Tesla finally started rolling out its adaptive headlights in North America. While the new Model Y already came with the feature when it was released last month, other vehicles with matrix headlights are now receiving the feature in the Spring Update.
All vehicles with matrix headlights are receiving this feature, which includes the new and old Model 3, first-gen Model Y, and the new Model S and Model X.
If you’re not sure if your vehicle includes matrix headlights, check out our guide. What’s interesting here is that older vehicles that were retrofitted with matrix headlights due to an accident or user replacement are also receiving the adaptive headlights feature.
Legacy Model S & Model X
As with most updates, the older legacy Model S and Model X are not receiving all the features included in this update. Unfortunately, some of the features, which include the Blind Spot Camera on the instrument cluster, Save Trunk Height Based on Location and Keep Accessory Power On are limited to the new Model S and X.
Legacy S and X models will receive the Alternative Trip Plans feature, Avoid Highways (Requires Intel MCU) and the Keyboard Languages feature.
These vehicles are also receiving all the features in the Minor Updates section except for the visualization showing how far the door is opened, which is exclusive to the Cybertruck. These additions include improved music search results, contact photos in the phone app, automatic connecting to hotspots, the ability to show third-party chargers, view Supercharger amenities, and various improvements to music services.
While many users will be disappointed not to receive the B-pillar camera recording and Dashcam Viewer improvements, it’s important to remember that Tesla typically does a great job at bringing features to older vehicles, at least with the Model 3 and Model Y. If a feature isn’t added, it’s usually due to a hardware limitation.
![Tesla Semi Keynote: New Features, 46 Charging Sites, Upgraded Battery & More [VIDEO]](https://www.notateslaapp.com/img/containers/article_images/semi/semi-new-features.jpg/c7df4e0d32f8cb0beee080ad201e943b/semi-new-features.jpg)
