Tesla FSD V12.5.5 Adds End-to-End Highway Stack; Tesla Teases Upcoming Features

By Karan Singh
Not a Tesla App

Tesla has launched FSD V12.5.5 with update 2024.32.20, which has just hit early access testers. This update includes several new things, including the new end-to-end highway stack and bringing FSD to the Cybertruck for the first time. Tesla also outlined additional features to expect in future revisions of FSD.

The End-to-End part of the stack means that rather than hand-coding all the decision-making directly into FSD, Tesla now relies upon AI, trained upon hundreds of thousands of hours of footage gathered by its fleet, to make decisions.

This is key to rapid improvements and will help to bring Unsupervised FSD – and Robotaxi – to realization. We’re especially excited to see these improvements with the Robotaxi event just around the corner.

End-to-End Highway Stack

FSD V12 brought the End-to-End stack to City Streets, and the Highway Stack was still running FSD V11. With this update, end-to-end AI will now be used on the highway, which should be a considerable improvement.

When End-to-End was introduced on city streets, it brought some drastic improvements in how FSD was handled between V11.4.9 and V12.3.6. There’s likely going to be a similar level of improvement between FSD V12.5.4 on the highway and FSD V12.5.5 on the highway.

As of today, FSD still tends to sit in the left lane, Auto-Speed doesn’t function on the highway, and the speed limit can change drastically where it's incorrectly mapped.

With the end-to-end highway stack, we could see FSD correctly use the left lane to overtake vehicles and then come back into the middle or right lane, as required. In addition, we could see Tesla add Auto-Speed functionality for the highway so that the vehicle is able to more fluidly respond to changes in traffic and speed more naturally.

Upcoming Improvements

In the release notes for FSD 12.5.5, Tesla also updated the list of features coming in future FSD versions, some of which Tesla hadn’t previously discussed or mentioned in the FSD Roadmap. In Tesla’s release notes, they specifically mention these upcoming improvements:

  • Earlier and more natural lane change decisions

  • Improved performanec in parking lots

  • Improved performance at intersections and stops

  • Introduction of Speed Profile

Earlier and More Natural Lane Changes

First off, Tesla mentions earlier and more natural lane change decisions. We’ve seen this one pop up before, and it's definitely a pain point for Tesla. Even today on FSD V12.5.4, FSD will still sometimes make lane change decisions within less than 200 feet of a turn, moving you from the far right to the left turning lane in a short space.

Addressing this will greatly help how smooth FSD will feel.

Improved Performance in Parking Lots

Tesla also mentions improved parking lot performance as coming soon. This particular enhancement to FSD will likely help improve Actually Smart Summon so that it can expand beyond FSD-specific updates and become available to more users. This will allow users with Enhanced Autopilot and owners outside of North America to gain access to Actually Smart Summon for the first time. Currently, Actually Smart Summon is available to users in North America with 2024.27.25.

In addition, we’re expecting Banish – also known as Reverse Summon – to rely upon these improvements. Banish will allow your vehicle to drop you off at an entrance to a location, and then find a parking stall, and park itself. This is going to be another key item for Robotaxi and Unsupervised FSD and is one of the items we’re the most excited about.

Improved Performance at Intersections and Stops

FSD V12.5 brought along some oddities regarding intersections. Owners have been reporting FSD stopping for green lights or double braking on stop signs. This feature is likely to target some of these existing issues.

While FSD V12.5 also brought pretty drastic improvements for roundabouts, there are still some issues with signalling and lane selection in multi-lane roundabouts, so maybe they’ll address those here as well. This is a pretty broad category, so we can only imagine what they’ll be doing here.

Introduction of Speed Profile

We previously reported that Elon Musk wanted to add a new FSD drive mode. It appears that FSD’s Assertive Mode will become “Hurry Mode.” However, based on the release notes, Tesla seems to imply that it may not be called Hurry Mode but instead Speed Mode. This mode will likely be an option that tells FSD to go a bit faster and also become more aggressive with overtaking – something that has become more common and much smoother with FSD V12.5. This is going to be an interesting addition or change, and we’ll be sure to dig into it more in the future when it becomes available.

Release Date

Tesla’s Autopilot director Ashok Elluswamy posted on X that while the Cybertruck is receiving FSD 12.5.5 with the end-to-end highway stack, don’t expect it to roll out to other vehicles immediately. Tesla prioritized getting this out for the Cybertruck and they’re still working on getting the highway stack ready for other vehicles. Ashok said that he expects Tesla to have an internal build ready in about a week or so. With Tesla’s robotaxi event just 10 days out, it sounds like this won’t arrive on customer vehicles until after the event.

Tesla Intel Atom (MCU 2) and AMD Ryzen (MCU 3): Feature Differences and How to Tell What You Have

By Karan Singh
DirtyTesla

Tesla vehicles are equipped with two main computer systems: the MCU (Media Control Unit), which is responsible for entertainment and display functions, and the Autopilot/FSD Unit, often referred to as the FSD Computer.

Both of these systems have evolved over the years, and they’re commonly referred to by their generation. For example, MCU 2 refers to the second generation of the Media Control Unit. Similarly, the FSD computer is identified by its generation, often called Hardware 3 or Hardware 4, when referring to the third and fourth-generation hardware. More recently, Tesla has started referring to the FSD Computer as AI3 and AI4, but you’ll still hear the older terms used interchangeably.

These two systems are separate and they’re not upgraded at the same time, meaning it’s possible to have a vehicle with MCU 2 and FSD Hardware 3 or MCU 3 with Hardware 3. Some vehicles even feature MCU 1 alongside Hardware 3.

The MCU is not involved with Autopilot or FSD functions—it’s purely for infotainment and in-vehicle features such as vehicle visualization, gaming, maps, and entertainment. It doesn’t impact the capabilities or limitations of Tesla’s autonomous driving systems.

MCU 1 - NVIDIA Tegra 3

MCU 1 was the first media control unit to be introduced in Tesla vehicles, starting back in 2012. This system was used in the Model S and Model X until about April 2018, when Tesla began transitioning to MCU 2.

By the time the Model 3 launched in late 2017, it already included MCU 2. To keep legacy vehicles up to date, Tesla offers an infotainment retrofit that upgrades MCU 1 to MCU 2, which helps make the infotainment unit much more responsive and adds a variety of newer features. Tesla continues to support vehicles with MCU 1, although upgrades are much further apart. In 2024, Tesla added Automatic Emergency Braking (AEB) improvements to vehicles with MCU 1 and even support for FSD V12.3.6 (FSD HW3 required).

Period Offered: 2012 through April 2018

Upgrade: Available as a paid upgrade for Model S and Model X vehicles to go from MCU 1 to MCU 2.

MCU 2 - Intel Atom

The launch of the Model 3 introduced MCU 2, which ran on Intel’s Atom mobile processor. While the Intel Atom was capable at the time, it’s now considered outdated compared to modern standards. As Tesla continues to roll out new features, the limitations of the Atom processor have become more apparent.

There is a notable list of features that are unavailable to vehicles with MCU 2. Although Tesla has optimized software to improve compatibility, not all features have been made accessible to these vehicles.

Period Offered: MCU 2 was offered in 2017 (Model 3) through 2022 (availability differs based on region and model).

Upgrade: As of now, Tesla has not offered an upgrade path or retrofit to transition from MCU 2 to MCU 3, and they’re unlikely to do so.

MCU 3 - AMD Ryzen

In December 2021, Tesla began shipping vehicles with MCU 3, powered by AMD’s Ryzen processor. The first vehicles to feature MCU 3 were the refreshed Model S and Model X, which debuted in 2021. Shortly after, Model 3s and Model Ys were also equipped with MCU 3, and today, all Tesla vehicles, including the Cybertruck, come standard with MCU 3.

This MCU is now the most widely used on the road and is Tesla’s most advanced infotainment processor. It supports impressive 3D visualizations, allows improved gaming on the center touchscreen (and rear screens in equipped vehicles), and offers a host of other capabilities. MCU 3 is also the most feature-complete version, with new features being designed for it first and then backported to MCU 2 or MCU 1 when possible.

Period Offered: The first MCU 3 vehicles were released in December 2021 and is current through today.

Upgrade: MCU 3 is the most current infotainment unit that Tesla offers.

Features Missing on MCU 2 (Intel Atom)

High-fidelity park assist is limited to vehicles with MCU 3
High-fidelity park assist is limited to vehicles with MCU 3
Not a Tesla App

While Tesla does its best to continue to support MCU 2, there is a growing difference between the features available on a vehicle with an Intel Atom infotainment unit and one with the AMD Ryzen processor.

Feature

MCU 2

MCU 3

Games / Arcade

⚠️ Limited Games*

✅ Additional Games**

Parked View

⚠️ Split screen visualization with vehicle on left and map on right

✅ Full-screen Parked Viz - Shadows, Sun Reflections, Shadows

Vehicle Visualizations 

⚠️ Some limitations, such as non-transparent glass

✅ Improved visualizations

Full-Screen FSD Visualization

⚠️ Only Available in North America

✅ Available in All Regions

Zoom Meetings

❌ Not Available

✅ Available

High Fidelity Park Assist

⚠️ Top-Down Visualization Only

✅ Full 3D Visualization

Autopark Visualizations (video)

⚠️ Top-Down Visualization Only

✅ 3D Visualization

Improved UI for Display Modules - Media, Next Turn, Trip Planner

⚠️ Solid Color/Semi-Transparent

✅ Transparency + Background Blur for Display Modules

*Many recent game additions are available to MCU 3 only, including the ever-popular Vampire Survivors and Castle Doombad. Only certain Model S and Model X vehicles include a GPU and the ability to play games on Steam.

**Atari Games were removed from MCU 3 vehicles due to Emulator Licensing issues.

How to Tell - Intel or AMD

Identifying which MCU your vehicle has is straightforward. Simply go to Vehicle Options > Software > Additional Vehicle Information.

In the interface, you’ll find details about whether your vehicle is equipped with an Intel Atom (MCU 2) or AMD Ryzen processor (MCU 3).

MCU 4?

It’s been more than three years since Tesla introduced the AMD Ryzen-powered MCU. Despite advancements, including the transition from FSD Hardware 3 to AI4—and eventually AI5—there’s been no indication of an MCU 4 on the horizon.

The Ryzen processor’s impressive capabilities make it a solid choice for infotainment, and it’s well-suited to serve until there’s another big leap in CPU performance.

While Tesla will upgrade to MCU 4 at some point, it doesn’t seem imminent. Some may argue that Tesla transitioned to MCU 3 too late, leaving vehicles just a few years old feeling outdated. It’s possible Tesla might choose to introduce MCU 4 ahead of the need for more processing power, ensuring that older vehicles can continue to benefit from new software features in the future.

Tesla Expected to Add Turn Signal Stalk Back to Model 3

By Karan Singh
Not a Tesla App

Following the surprising return of the turn signal stalk on the refreshed Model Y, reliable Tesla source Chris Zheng has indicated that the Model 3 will also be receiving a turn stalk. While it initially seems surprising, Tesla mentioned that after receiving lots of customer feedback, there is a lot of demand for the return of the stalk.

For those who appreciate the newer turn signal buttons on vehicles like the Cybertruck, this might come as a surprise. However, the Model 3 and Model Y are designed for the average driver transitioning from a traditional vehicle, making the removal of the turn signal stalk an unexpected and potentially disappointing change.

Turn Stalk

In a conversation during the latest episode of Jay Leno’s Garage, Tesla’s VP of Vehicle Engineering, Lars Moravy, mentioned that Tesla works to remove superfluous parts. In this case, they removed one part too many - and are now bringing back the turn signal stalk.

The updated stalk on the refreshed Model Y is a simplified version of the current Model Y stalk. It doesn’t include multi-stage turn signals (short three flashes versus staying), buttons, or other features. Pure and simple - it is utilized for signaling left and right. The rest of the functions of a traditional stalk remain either on the wheel or on the screen.

Lack of Right ‘Shifter’ Stalk

Tesla has no intent to bring back the right stalk, which is traditionally used to shift the vehicle from Drive to Reverse and Park in Teslas. It’s also used to activate Autopilot. The shifting functionality will remain on-screen or available via the backup by tapping the buttons on the ceiling near the hazards button. Shifting via the dash is intuitive and convenient once you get used to it - and with AutoShift hopefully coming out of Beta sometime soon, this could get even better.

Autopilot activation will remain with a button on the steering wheel. While a vehicle with a single stalk may look a little odd at first, Lars mentioned that Tesla didn’t receive many complaints about shifting or Autopilot use.

Retrofit

Not a Tesla App

We haven’t heard anything about retrofitting the 2024+ Model 3s with the turn signal stalk at this point. However, we imagine this may be a possibility in the future.

However, we can recommend using the wireless Enhauto’s S3XY Stalks if you want to bring a single or dual stalks back to your refreshed Model 3 and don’t want to wait for an official retrofit to arrive. They’re easy to install, well-designed, and reliable.

Other Models

The big question now is: will Tesla bring back the turn signal stalk for its other models? It’s possible, but we doubt it. The Model S and Model X, especially with the Yoke, feel more natural without a stalk, and the button-based signals suit their design. While a stalk might occasionally be useful—like signaling in and out of a roundabout—any future refresh of the S or X would likely include steer-by-wire instead.

On the Cybertruck, the absence of a stalk goes unnoticed, thanks to steer-by-wire, as the squircle steering wheel is never in an awkward position. After thousands of kilometers of daily driving, including plenty of roundabouts, the author can confidently say the signal stalk isn’t missed at all. In fact, the turn signal buttons feel more intuitive, given how the Cybertruck handles.

That said, could Tesla offer signal stalks as an option for those who prefer them? It’s not out of the question. We’ll keep you updated, but in the meantime, let us know—do you prefer turn signal buttons or a traditional stalk?

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