If you disable NM, you need to enable network. From a local console (in other words, don't do this over a network session like ssh):
systemctl disable NetworkManager.service systemctl stop NetworkManager.service systemctl enable network systemctl start network
Thomas
Unfortunately the device is sill named em1, not eth0. So it's not NM. I don't understand why the udev rules files are ignored. Bug maybe? I'll report it and see what happens.