I am trying to sign the VirtualBox kernel modules using Fedora 27 with UEFI Secure Boot enabled. I have successfully signed the modules and have run
sudo mokutil --import MOK.der
where MOK.der is the output file from generating the key. When I reboot, I am greeted with a message: Press any key to run MOK Management. A countdown to boot normally is shown in the bottom left of the screen. When I press a button, the countdown freezes, but nothing else happens. I have determined through pressing keys that the MOK Manager is loaded, but is not displayed on the screen.
My issue is identical to the one described on askubuntu here. The person who asked the question fixed the problem by following screenshots of what they should be seeing. I have not found any screenshots of the setup process, but I do have a laptop that I have done the same process on successfully. I may be able to get through the process blind, although I have already tried once to follow the same process of adding a new key unsuccessfully.
I would like to fix the underlying issue though, since I'm apparently not the only one experiencing it. What troubleshooting steps can I take to isolate the cause of the MOK Manager not displaying?
ASRock Extreme4 X99 Motherboard, UEFI version 3.60 (most recent available)
Intel i7 5820K cpu
Sapphire Radeon R9 280X Tri-X gpu
OS: Fedora 27, kernel version 4.14.16-300.fc27.x86_64