Reliable 25 Gigabit Ethernet via Thunderbolt

Re:Reliable 25 Gigabit Ethernet via Thunderbolt by kohlschuetter on Sunday February 01, 2026 @08:44AM (#46846170)

Thanks! Have you tried the boltctl/rescan setup I mentioned in the post? It should get you going, as long as your Thunderbolt/USB4 setup is correct.

If you're using an adapter card to add Thunderbolt functionality, then your mainboard needs to support that, and the card must be connected to a PCIe bus that's wired to the Intel PCH, not to the CPU.

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Re:Reliable 25 Gigabit Ethernet via Thunderbolt by madduci on Sunday February 01, 2026 @08:59AM (#46846263)

Yes, rescan, re-enroll too. But it still shows as disconnected. I don't know if the firmware is completely incompatible, but it is weird that under windows works and in Linux doesn't

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Re:Reliable 25 Gigabit Ethernet via Thunderbolt by kohlschuetter on Sunday February 01, 2026 @09:10AM (#46846335)

Disconnected as in "network"? What PCIe card do you use? Can you update the firmware (maybe from Windows)?

Also check the BIOS settings (try setting TB security to "No Security" or "User Authorization")

Some OEM Mellanox cards can be cross-flashed to NVIDIA's stock firmware, maybe that's also relevant.

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Re:Reliable 25 Gigabit Ethernet via Thunderbolt by madduci on Sunday February 01, 2026 @01:31PM (#46848178)

It's embedded in the laptop (a HP ZBook from work). Disconnected as in network. Laptop charges, but signal doesn't work. With Thunderbolt 3 devices, it works. (The card itself is T4).

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