Comment 5 for bug 1848880

I can't tell you how many times I tried this and each time was the same - menu showed OEM mode, but oem-config-prepare was not found once booted. I had even downloaded ubuntu-18.04.3-server.iso, ubuntu-18.04.2-server.iso, ubuntu-18.04.1-server.iso, and the original 18.04-server and tried with them to no avail.

Today, after seeing your comment I decided to try it again with the same exact steps and it worked! While intensely curious as to why it didn't work before, I will just be thankful that it does now so I can create my template VM :-)

If it resurfaces at a later date, I will bring it up again (with logs of some sort and maybe a video so I don't seem as crazy).