From Ubuntu 20.04.3 on, the boot files (vmlinuz and initrd) are no longer available at 'dists/$release/main/installer-$arch/current/legacy-images/netboot/' + guess_os + '-installer/$arch' (see [here](http://archive.ubuntu.com/ubuntu/dists/jammy/main/installer-amd64/current/legacy-images/)).

The boot files are available at 'casper/[vmlinux|initrd]' (see [here](https://ubuntu.com/server/docs/install/autoinstall-quickstart)). Accordingly, the path for Foreman to search the images when applying the installation media must change too.