Fixing Intel NUC Ethernet using Money

My 2020 Intel NUC running Proxmox had an Ethernet port issue (randomly ‘locking up’) caused by firmware issues in the Intel I225-V chip.

I tried all the solutions that I could find:

• Flashing a new “NVM” version onto the chip using Intel NVM Update. Didn’t work because I have chipset 15F3 and I wasn’t able to find anything new for that.
• Turning off LAN power saving and activating LAN performance mode via kernel: GRUB_CMDLINE_LINUX_DEFAULT="quiet pcie_port_pm=off pcie_aspm.policy=performance". This did extend how long the port stayed alive, but it didn’t fix the problem.

The final fix: Using a €22 UGREEN 2.5G USB 3.0 to Ethernet adapter resolved the issue. The interface saturates properly in tests (iperf3):

[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-30.00  sec  3.29 GBytes   942 Mbits/sec   43             sender
[  5]   0.00-30.00  sec  3.29 GBytes   941 Mbits/sec                  receiver

(my switch only has 1gbit ports)