No Ethernet connection with Lenovo Docking Station Thunderbolt
I'm using a Lenovo X13 Yoga Laptop connected to a Lenovo Universal Thunderbolt 4 Dock with a thunderbolt cable. Further the docking station has two screens and an Ethernet cable attached. The laptop is running Ubuntu 20.04.4 LTS and the kernel version is 5.13.0-37-generic
Today Ubuntu asked me to install new updates. After the updates I restarted the laptop and then my Ethernet connection from the Docking station to the LAN didn't work anymore. However if I connect the Ethernet cable directly to the laptop I get access to the internet.
According to the history.log it installed the following stuff:
Start-Date: 2022-03-22 09:20:48
Commandline: /usr/bin/unattended-upgrade
Install: linux-image-5.13.0-37-generic:amd64 (5.13.0-37.42~20.04.1, automatic), linux-modules-extra-5.13.0-37-generic:amd64 (5.13.0-37.42~20.04.1, automatic), linux-modules-5.13.0-37-generic:amd64 (5.13.0-37.42~20.04.1, automatic), linux-headers-5.13.0-37-generic:amd64 (5.13.0-37.42~20.04.1, automatic), linux-hwe-5.13-headers-5.13.0-37:amd64 (5.13.0-37.42~20.04.1, automatic)
Upgrade: linux-headers-generic-hwe-20.04:amd64 (5.13.0.35.40~20.04.20, 5.13.0.37.42~20.04.22), linux-image-generic-hwe-20.04:amd64 (5.13.0.35.40~20.04.20, 5.13.0.37.42~20.04.22), linux-generic-hwe-20.04:amd64 (5.13.0.35.40~20.04.20, 5.13.0.37.42~20.04.22)
End-Date: 2022-03-22 09:21:14
Start-Date: 2022-03-22 09:21:17
Commandline: /usr/bin/unattended-upgrade
Upgrade: linux-libc-dev:amd64 (5.4.0-104.118, 5.4.0-105.119)
End-Date: 2022-03-22 09:21:17I checked in the BIOS if it is still forwarding the MAC address from the laptop to the docking station, what it does. I'm not a Linux pro, so I can't really tell what went wrong. I guess one of the updates did something bad. The previous kernel was 5.13.0-35-generic. Should I try to downgrade to that? Would that break anything? I haven't installed anything new except the updates from above. Any ideas?
EDIT: I downgraded the kernel to 5.13.0-35-generic and now the ethernet connection is working again. Where do I find the kernel repositories for the two mentioned kernel versions for trying to figure out where the problem might be? I can't find the kernels I have to do with on They start enumerating from 5.13.1 but I have 5.13.0
