Comment 13 for bug 1988504

I have also experienced this problem. It took a pretty long time to figure out why my USB Ethernet adapter worked just fine on the Ubuntu host but would never work correctly on the Ubuntu or Home Assistant OS guests.

For whatever its worth, I experienced this problem on several different Realtek 8152 (10/100) and 8153 (Gigabit) USB ethernet adapters from multiple manufacturers. My ASIX Ethernet adapters (88179 and 88772) pass through to guests just fine. I have multiple guest VMs and I wanted to be able to provide a gigabit NIC for each without having to deal with USB paths.

I had to blacklist the r8152, r8153_ecm, and cdc_ether modules on the host to get the passthrough to work correctly. I would like to confirm that the '$ sudo update-initramfs -u' step IS necessary to get this to work.

Thanks Christian Ehrhardt.