Bug 1955936

Description of problem:
Installation fails near the end with a screen saying "failed to write boot loader configuration".  The computer is left in an unbootable condition.


Version-Release number of selected component (if applicable):
Fedora-Server-netinst-x86_64-34-1.2.iso

How reproducible:
Always

Steps to Reproduce:
1. Boot from DVD burned with above netinstall iso.
2. Choose XFCE and install to a partition
3. Installer stops after successful download & installation of packages

Actual results:
A screen pops up with the message:
"The following error occured while installing the boot loader.  The system will not be bootable.  Would you like to ignore this and continue with the installation?

failed to write boot loader configuration"

As predicted, the computer will not boot.


Expected results:
Completion without error; the computer boots to the new system.


Additional info:
Examination of the journal showed that the error occurred during execution of grub2-mkconfig, with the message:
/usr/sbin/grub2-probe: error: ../grub-core/kern/fs.c:120:unknown filesystem

I chose the option to complete the installation, and tried to boot the new system.  The boot failed, and took me into a grub shell.

I then booted from the DVD, choosing to recover the new system.  I chrooted into the new system and executed grub2-mkconfig.  It failed with the same grub2-probe error.

My system has multiple Fedora systems, so I booted my Fedora 33 partition, chrooted into the new F34 system, and executed grub2-mkconfig with no errors.  I don't understand this: the two environments should be almost identical.

Some other information which might be pertinent:
My computer uses Secure Boot, and is able to boot to different Fedora systems because each has a separate entry in efibootmgr which points to its own subdirectory under /boot/efi/EFI.  Each of the Fedora systems exists in a separate partition of /dev/sda; there is also a Windows 10 system on that disk.