Bootloader recovery

ErgenCTL can rebuild an installed ErgenOS bootloader from the ErgenOS Live ISO. It backs up /boot, rebuilds initramfs and GRUB, regenerates the Btrfs snapshot menu and restores the ErgenOS Secure Boot firmware entry when Secure Boot was configured.

Boot the Live ISO with Secure Boot disabled

ErgenOS 1.2 installation media does not boot with Secure Boot enabled. Disable it temporarily in firmware. The installed system's MOK keys remain unchanged.

1. Identify the installation

List disks and filesystems:

lsblk -o NAME,SIZE,FSTYPE,FSVER,LABEL,UUID,MOUNTPOINTS

Identify the installed ErgenOS root filesystem. Do not copy device names from an example: selecting the wrong partition can damage another installation.

For the standard Btrfs layout, inspect its subvolumes before mounting it:

sudo mkdir -p /mnt/ergenos-top
sudo mount -o subvolid=5 /dev/ROOT-PARTITION /mnt/ergenos-top
sudo btrfs subvolume list /mnt/ergenos-top

The standard ErgenOS root subvolume is @.

2. Mount the installed root

sudo mkdir -p /mnt/ergenos
sudo mount -o subvol=@ /dev/ROOT-PARTITION /mnt/ergenos

ErgenCTL reads the installed system's fstab and mounts its separate /boot, /boot/efi and /.snapshots filesystems during recovery.

3. Run the graphical recovery

Open ErgenCTL in the Live environment and select Recover installed bootloader. Confirm /mnt/ergenos as the mounted root, choose Show plan, review the result and then run Repair bootloader.

This action is shown only in the ErgenOS Live environment.

Command-line alternative

Always inspect the plan first:

sudo ergenctl fix bootloader --root /mnt/ergenos --dry-run
sudo ergenctl fix bootloader --root /mnt/ergenos --yes

The repair succeeds only after validating the kernel and initramfs, the normal EFI loader, the main GRUB configuration, the generated snapshot menu and recursive grub-btrfsd monitoring. When Secure Boot is configured it also rebuilds the signed GRUB image, restores its UEFI entry and verifies existing kernel signatures without rebuilding unrelated DKMS modules.

4. Restart and verify

After a successful report, unmount the filesystems and restart. If Secure Boot was configured, select ErgenOS Secure Boot. Confirm that GRUB contains both the normal ErgenOS entry and ErgenOS Snapshots, then boot the installed system.

Do not continue after a failed report

ErgenCTL restores its /boot backup when validation fails. Read the reported cause and correct it before restarting or repeating the repair.