Comma.ai Launches A PCIe Gen4 x4 To USB4 Dock With Open-Source Firmware

Written by Michael Larabel in Hardware on 12 August 2026 at 08:35 PM EDT. 19 Comments
HARDWARE
George Hotz of Comma.ai and Tinygrad today announced the Tiny Chestnut eGPU Dock and the "Chestnut" Dock complete with an AMD Radeon RX 9060 8GB GPU too. Making this Chestnut / Tiny Chestnut Dock interesting is that it runs on open-source firmware.

The primary focus of Comma.ai launching the Chestnut is to allow for larger driving models for their advanced driver-assistance systems. Rather than being bound to the 10 Watt compute footprint currently, with the Chestnut it can be expanded out to 100 Watts and using the likes of a Radeon RX 9060 can handle larger models.

This comes as Comma.ai launches a new 1B parameter driver model wth the soon-to-launch OpenPilot 0.11.2. With this glorified eGPU dock, they even note you can then mount your graphics card under the seat or in the passenger footwell of your vehicle.

Chestnut installed


All those details can be found on the Comma.ai blog. Making it more interesting to us is that it can also be attached to your typical PC too and not limited to just working with Comma.ai driving systems. Plus it's running on open-source firmware. The firmware is published on GitHub and is a C-based firmware for the ASM2464PD USB4/Thunderbolt to NVMe bridge controller.

The Chestnut can be connected to a computer for use similar to other USB4 docks. It's also compatible with Tinygrad usage.

Tiny Chestnut


The Tiny Chestnut eGPU Dock on its own is retailing for $249 USD. Or The Chestnut with the Radeon RX 9060 included is currently $799 USD. Those wanting to learn more can do so via Comma.ai.
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