Comment # 6 on bug 1232696 from Stefan Hundhammer

To get your system up and running again quickly, you might want to check
/etc/sysconfig/bootloader if there are any weird values there. I have:

% grep '=' /etc/sysconfig/bootloader
LOADER_TYPE="grub2-efi"
SECURE_BOOT="yes"
TRUSTED_BOOT="no"
UPDATE_NVRAM="yes"

On my legacy (non-UEFI) boot machine:

% grep '=' /etc/sysconfig/bootloader 
LOADER_TYPE="grub2"
SECURE_BOOT="yes"
TRUSTED_BOOT="no"
UPDATE_NVRAM="yes"