I have recently started using the ethernet instead of wifi. I have not disabled
the wifi, but I leave the ethernet cable inserted. Recently, I noticed that I was
unable to start the computer. I thought it was a faulty F37 testing kernel, so I
tried the previous kernel. Same thing. For some reason, I thought the only
thing different is that I now have the ethernet hooked up, so I pulled the plug
and tried to boot. Everything went fine.
How come I cannot boot the computer with the ethernet cable plugged in?
I recently did the reverse (system was running reliably on ethernet, but
switched to wifi and then didn't boot after an update was applied). Journalctl
revealed that the update had lost the ability to mount the (hfsplus format) EFI
partition. After reinstalling the update, wifi is working.
Use journalctl to collect evidence. It may also be useful to search across other
distros (particularly arch) for similar problems with your ethernet hardware.