Repair/Reinstall GRUB after Windows 11 Update (Dual Boot Fedora F39)

Ask Fedora
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7

Your instructions are great for systems using MBR boot, but do not account for the changes from ext4 to btrfs and sub-volumes, nor do they account for use of UEFI.

Windows 11 only uses UEFI so the fedora install also uses UEFI and proper instructions must reflect that.

When in the live system first make certain that the internet connection is properly functioning.
Then to mount the root subvolume with a btrfs file system it would be necessary to identify the btrfs partition with lsblk -f then mount it as.

  1. su to enter the root user environment
  2. mount -t btrfs -o subvol=root,compress=zstd:1 UUID=<uuid of btrfs partition> /mnt
    then mount the other needed system file systems as
  3. for fs in proc sys run dev sys/firmware/efi/efivars ; do mount -o bind /$fs /mnt/$fs ; done
  4. chroot /mnt
  5. mount -a which will then mount the remaining file systems for the installed system according to the /etc/fstab entries.
  6. then perform the steps above to repair grub.

I have not tried systemd-nspawn but if that works as it appears from the man page then it may be possible to replace my steps 3 thru 5 with the systemd-nspawn command given above.