Tesla (TSLA) has finally fulfilled its promise of providing a stable FSD Supervised version to the legacy Model S and Model X vehicles with the MCU1 infotainment system.
The automaker started rolling out the FSD v12.3.6 update to MCU1 vehicles a few days ago. These older Model S/X vehicles have the legacy Nvidia Tegra graphics processor (GPU) and the slower center touchscreens. This setup creates a performance lag when processing Autopilot/FSD driving visualizations and other infotainment features.
Tesla offered a $2,000 retrofit to upgrade the system to MCU2 with the newer Intel Atom-based GPU (MCU2). The majority of these legacy Model S/X owners opted for the upgrade but there’s a chunk of owners still having MCU1 in their vehicles. MCU stands for Media Control Unit — a term coined by Tesla for the new-age infotainment systems.
Tesla has bundled the FSD v12.3.6 with the Summer Update version 2024.26.3.1. The specific point release having 3.1 at the end of the firmware version is related to the MCU1 Tesla cars.
The rollout of the v2024.26.3.1 update brings dual joy for MCU1 Tesla owners as they also get the latest features of the 2024 Summer Update v2024.26 and its subversion point releases.
A legacy Tesla Model S owner with the MCU1 infotainment system shared the screenshot of his vehicle’s center touchscreen showing the FSD v12.3.6 update download notification on Reddit.
According to the install notification after download, the FSD v12.3.6 (2024.26.3.1) update takes approximately 50 minutes to be installed on MCU1 Tesla cars.
According to the Tesla software tracking website TeslaFi.com, the MCU1 FSD v12.3.6 update (2024.26.3.1) has been installed on 792 Tesla Model S/X vehicles and 24 installations are pending as of this writing. These 800+ MCU1 cars are part of the 20,000+ data-contributing Tesla cars on the tracking platform.
MCU1 cars with the FSD v12.3.6 update can be identified with the specific point release firmware version 2024.26.3.1.
If you’re an MCU1 Tesla owner, let us know your thoughts in the comments section below. Stay tuned for future news on Tesla software updates.
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 rolls out the FSD v12.3.6 software update with the Summer Update (2024.26.3.1) to legacy MCU1-based Model S and Model X vehicles.){kind=link}
The biggest chunk of Tesla vehicles left out of this upgrade are all Legacy vehicles. Legacy means that they have the portrait screen and are either Model S or Model X, and no cabin camera. Virtually all of these vehicles still on the road are MCU2 and HW3 based. The hardware is identical to the M3 and some MY, just a different screen orientation and configuration, and no cabin camera.
These cars are being left out of the FSD upgrade, while older Model 3 vehicles are being upgraded. To add to the frustration, they were, at the time of purchase, Tesla’s most expensive vehicles. Those who purchased FSD in these vehicles are not receiving what they were promised, what was paid for, or what is possible. They are being left out.
It remains to be seen what Tesla will do to remedy this injustice. Whether that will take the form of a refund as a few have gotten, a hardware fix, or a free transfer to their next car, only time will tell.