I upgraded a fairly old VyOS system from 1.0.3 to 1.1.7 and upon restart I found that my eth0 configuration was missing. Everything was working correctly and eth0 had the right address, but configurations such as assigned firewall rulles were missing. When I tried to load the boot.config file or recreate the eth0 configuration, I received the following error:

[ interfaces ethernet eth0 ]
rm: cannot remove `/tmp/speed-duplex.eth0': Operation not permitted

I was able to get around this by removing the /tmp/speed-duplex.eth0 file. I'm not sure what created this file in the first place.