Tesla pushed FSD V12.5 with update 2024.20.10 to additional vehicles last night. For the first time, FSD v12.5 also went out to additional Tesla models, however, it’s still limited to hardware 4 vehicles.
Support for FSD V12.5
FSD V12.5 is only available to vehicles with hardware 4 vehicles, or as Tesla is now calling the hardware, AI4. Before yesterday the update was limited to just Model Y vehicles on HW4, but Tesla quickly expanded it to all vehicles besides the Cybertruck and Semi, which has yet to see any Autopilot features.
Musk commented on X that he wanted to focus on improving the software on specific hardware before expanding it to additional hardware and vehicles.
FSD v12.5 has a 5X increase in operating parameters. This is a large increase and Musk said that it currently won’t be able to run on hardware 3 until the code is optimized.
We are focusing on just Model Y with HW4 for the initial release. Make sure that works well, then broaden.
This has the 5X increase in parameters.
HW3 would run the same parameter count, but requires extra work to optimize the code.
Ashok Elluswamy, Head of AP at Tesla, also mentioned that the focus for V12.5 was on both safety and smoothness for this release. His personal test – not spilling an open cup of coffee while on FSD. On V12.5, Ashok made it 30 minutes without spilling coffee. This is good news, as the smoother and safer FSD gets, the more natural it feels for the driver and occupants in other vehicles.
HW4/AI4
Following all this up is a recent post on X from Elon mentioning that Hardware 4 will now be renamed to AI 4. Tesla is already training the HW4 computers in a loop with Nvidia GPUs, at a 1:2 ratio. This is surprising news, as Musk previously mentioned that training for Hardware 4/AI4 would only begin after the new Supercomputer cluster was finished.
It's good to see that training is already underway for AI4, but this also means we’re hitting the limits of Hardware 3 pretty fast. It has been mentioned that there will be a drastic hardware divergence in the future between Hardware 3 and AI4, but we weren’t expecting that until later this year.
This means that updates may get better, as Tesla’s AI4 is approximately 4-5x better in terms of resolution and fidelity than hardware 3, and hardware 4.0 is about 3-5x faster and more powerful in inference capabilities.
AI5
With AI5 scheduled 18 months away, including a 10x inferencing improvement, we’re wondering what the future of Hardware 3 and AI4 will look like within the next 3 to 5 years. Cars are long-time purchases for many people, and we’re hoping that Tesla continues to do their best work to optimize code wherever possible to continue supporting Hardware 3.
Tesla has specifically come out and said it doesn’t plan to support a retrofit from Hardware 3 to Hardware 4, likely due to the differing locations of electrical and coolant connections, as well as the form factor of the compute units themselves.
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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.
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