Tesla may have multiple versions of FSD hardware 4.0
@GreenTheOnly/Twitter
Since its introduction, Tesla's Hardware 4 (HW4), the company's most advanced full self-driving computer, has been shrouded in mystery. Renowned Tesla hacker @greentheonly, or Green, has uncovered more details about HW4, providing valuable insight into its technology.
2-SOC Version and Camera Layouts
Green's analysis of firmware samples led to the discovery of the shipping version of HW4, internally referred to as the 2-SOC (System on a Chip) version. This version supports two possible camera layouts: the current one or an expanded one with added surround-view cameras, such as a front bumper camera and two additional side cameras. These cameras can run at a resolution of 2880x1876 and reach up to 45 frames per second. The main and backup cameras have unique specifications, with the vendor yet to be determined.
The new Global Navigation Satellite System (GNSS) is reportedly based on the Teseo V platform, while the radar system connects via Ethernet and operates on an internal IP address of 192.168.90.110.
Initial HW4 Camera Connectors and New Cameras
Initially, Green revealed HW4 with 12 camera connectors, and new cameras were expected to be used in HW4 vehicles. However, the first vehicles with HW4, specifically the Model S and Model X, have the new hardware but do not include the new cameras. As previously reported in our Project Highland article, Tesla plans to add a new camera to the bumper and one more to each side of the vehicle.
Two HW4 Setups and the 3-SOC Version
Green's latest findings show two HW4 setups: one with additional cameras and one without. Additionally, Green's firmware analysis has uncovered the existence of a 3-SOC version in development. The camera layouts for this version remain the same, but the internal deserializing routing differs.
Increased heat output from the GPU in HW4 has possibily led to limitations in its capabilities. The 3-SOC version could potentially address this issue by offering better heat dissipation or paving the way for new hardware. However, the exact purpose and development of the 3-SOC version remain uncertain at this time.
Tesla Semi Truck-related Findings
In another intriguing development, Green's firmware analysis revealed information related to Tesla's Semi truck, with the Battery Management System (BMS) and all three subpacks accessible over an internal ethernet network.
These discoveries by @greentheonly provide a comprehensive understanding of the advanced technology behind Tesla's HW4. As the most advanced full self-driving computer on the market, its potential applications and capabilities are undoubtedly exciting for the automotive industry and consumers.
As Tesla continues to develop and refine its full self-driving technology, it is crucial to address questions about its safety, functionality, and integration with existing systems. The world eagerly awaits further developments in the cutting-edge HW4 and the autonomous driving experience it promises to deliver.
Tesla’s been on a roll with Supercharger improvements lately, from the 325kW charging update for the Cybertruck, to 500kW with V4 Superchargers coming next year. While those improvements have been limited to the Cybertruck, Tesla didn’t put all their focus on their new flagship vehicle, but looked at their more affordable vehicles as well.
LFP Battery Heating
Tesla’s Superchargers can now heat LFP Batteries - those that are in the Model 3 and Model Y Rear Wheel Drive variants. This applies to Long Range and Standard Range models, which saw a limited run. This is another update included as part of the 2024 Tesla Holiday Update - which really arrived with a lot of unannounced new features and capabilities.
The change is pretty interesting - Superchargers of the V3 and V4 variety can now pre-heat batteries for Model 3 and Model Y vehicles equipped with LFP battery packs. That means those vehicles are able to get back on the road faster when it's extremely cold. Of course, Tesla still advises you to precondition before you arrive, saving drivers time and money.
Max de Zegher, Tesla’s Director of Charging, also commented on the new feature. Essentially, Tesla is inducing an AC (alternating) ripple current through the battery to warm it up. Keep in mind that Superchargers are DC charging. That means it is possible to get a cold-soaked LFP vehicle on the road 4x faster than before, assuming that it didn’t precondition at all and that it is in the worst-case scenario (below 0ºF).
In essence, Tesla is using some engineering magic to turn the circuits inside the LFP battery into an electric heater - and powering that heater through the Supercharger. An AC ripple current is a small oscillation in the DC charging current that generates heat through electrical resistance, warming up the battery. Those ripples are a byproduct of converting AC to DC and back - so Tesla is using the onboard charger to induce those ripples to warm up the battery. Definitely an innovative technique that’s really only possible with the versatility of the NACS connector.
We’re hoping Tesla can implement this across their full lineup of vehicles, but we’ll have to wait and see how it is trialed across LFP vehicles first and if it is even possible on vehicles with 2170 or 4680 battery packs.
Tesla launched two FSD updates simultaneously on Saturday night, and what’s most interesting is that they arrived on the same software version. We’ll dig into that a little later, but for now, there’s good news for everyone. For Hardware 3 owners, FSD V12.6.1 is launching to all vehicles, including the Model 3 and Model Y. For AI4 owners, FSD V13.2.4 is launching, starting with the Cybertruck.
FSD V13.2.4
A new V13 build is now rolling out to the Cybertruck and is expected to arrive for the rest of the AI4 fleet soon. However, this build seems to be focused on bug fixes. There are no changes to the release notes for the Cybertruck with this release, and it’s unlikely to feature any changes when it arrives on other vehicles.
FSD V12.6.1 builds upon V12.6, which is the latest FSD version for HW3 vehicles. While FSD V12.6 was only released for the redesigned Model S and Model X with HW3, FSD V12.6.1 is adding support for the Model 3 and Model Y.
While this is only a bug-fix release for users coming from FSD V12.6, it includes massive improvements for anyone coming from an older FSD version. Two of the biggest changes are the new end-to-end highway stack that now utilizes FSD V12 for highway driving and a redesigned controller that allows FSD to drive “V13” smooth.
It also adds speed profiles, earlier lane changes, and more. You can read our in-depth look at all the changes in FSD V12.6.
Same Update, Multiple FSD Builds
What’s interesting about this software version is that it “includes" two FSD updates, V12.6.1 for HW3 and V13.2.4 for HW4 vehicles. While this is interesting, it’s less special when you understand what’s happening under the hood.
The vehicle’s firmware and Autopilot firmware are actually completely separate. While a vehicle downloading a firmware update may look like a singular process, it’s actually performing several functions during this period. First, it downloads the vehicle’s firmware. Upon unpacking the update, it’s instructed which Autopilot/FSD firmware should be downloaded.
While the FSD firmware is separate, the vehicle can’t download any FSD update. The FSD version is hard-coded in the vehicle’s firmware that was just downloaded. This helps Tesla keep the infotainment and Autopilot firmware tightly coupled, leading to fewer issues.
What we’re seeing here is that HW3 vehicles are being told to download one FSD version, while HW4 vehicles are being told to download a different version.
While this is the first time Tesla has had two FSD versions tied to the same vehicle software version, the process hasn’t actually changed, and what we’re seeing won’t lead to faster FSD updates or the ability to download FSD separately. What we’re seeing is the direct result of the divergence of HW3 and HW4.
While HW3/4 remained basically on the same FSD version until recently, it is now necessary to deploy different versions for the two platforms. We expect this to be the norm going forward, where HW3 will be on a much different version of FSD than HW4. While each update may not include two different FSD versions going forward, we may see it occasionally, depending on which features Autopilot is dependent on.
Thanks to Greentheonly for helping us understand what happened with this release and for the insight into Tesla’s processes.
