For UEFI all you need is the installer files and the boot loader stuff under the /efi folder, right? Well, RHEL doesn't seem to like it that way.
[  207.506530] localhost dracut-initqueue: Warning: Could not boot.
[  207.801528] localhost systemd: Received SIGRTMIN+20 from PID 1128 (plymouthd).
[  207.838198] localhost systemd: Received SIGRTMIN+21 from PID 1128 (plymouthd).
Umm. Cool. Then you find a bug ticket about it and figure out you might as well get it from the official repo.