Hey. Short story: I activated Secure boot on my MSI Mainboard and bootet in my new Debian. I realized that I had no wired internet connection and rebooted the system to deactivate secure boot again. Problem is that now my whole Ethernet is borked? I don’t get a connection in Debian or my older OpenSuse partition and the Debian install USB stick says that the connection doesn’t work. Of course I deinstallieren Windows and now this happens. Tried already a different cable . Any idea what I could do?
In your motherboard settings, are you in UEFI boot mode? Try changing to BIOS/Legacy. Driver firmware can act differently between the two.