My bootloader/startup program no longer works! - My bootloader/startup program no longer works! - TUXEDO Computers

The grub boot loader is a central element in the Linux ecosystem for the operating system’s boot process. Despite its reliability, occasional glitches can occur, whether due to updates, kernel changes, or system failures. This guide provides help in repairing the Grub boot manager of TUXEDO OS, OpenSUSE and Ubuntu (and derivatives) in a chroot environment.

TUXEDO OS

With TUXEDO OS we have introduced a significant simplification as far as creating a chroot is concerned. With the TUXEDO Chroot Helper you create a chroot with a few mouse clicks and without entering any commands. You can find the tool in the live medium of TUXEDO OS in the main menu under the menu item TUXEDO. We explain how to create a chroot environment with it in a separate article in the documentation of TUXEDO OS.

openSUSE

For openSUSE, you can find the necessary steps as well as detailed instructions in the distribution’s online manual.

Ubuntu

Preparations

Step 1: Create bootable USB stick with TUXEDO OS

You need a USB stick or a CD/DVD with a live system. If you do not have such a boot medium yet, the instructions Create live boot medium will help you.

Step 2: Boot computer as live system with TUXEDO OS

Start the live medium on your device. Here you have to note that the live medium is also booted in UEFI mode if the installed system (whose bootloader you want to recover) is also installed with UEFI.

Step 3: Determine the Device ID of the Boot Partition

You now create a chroot environment with your system in the terminal. Since all commands must be executed with root privileges, use sudo -s to obtain permanent administrative privileges. From then on, all entries in the terminal will be executed without the usual preceding sudo. Afterwards you inform yourself about the available hard disks and partitions (the output looks like this or something similar).

lsblk
(out)NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
(out)sr0     11:0    1  1024M  0 rom
(out)sda      8:0    0 232,9G  0 disk
(out)├─sda4   8:4    0 174,4G  0 part
(out)├─sda2   8:2    0     8G  0 part SWAP
(out)├─sda3   8:3    0    50G  0 part
(out)└─sda1   8:1    0   512M  0 part

You identify the partitions by their size: The EFI partition is always 512M in size, listed here as sda1. For older pre-installations of TUXEDO Computers machines or WebFAI installations, the root partition / was always 50G in size, for example, which would be sda3 here. In more recent installations, we no longer use a separate partition for the partition /home. The device ID of the root partition / corresponds to the largest partition there.

Step 4: Define variables for simplification

For convenient further operation, create temporary variables and enter the device paths according to the info from the previously mentioned command lsblk. Do not forget to adjust the device IDs in the commands.

myefi=/dev/sda1
myroot=/dev/sda3

Devices with UEFI enabled

You now mount the root partition and prepare other functions for the chroot environment. Then mount the EFI partition, switch to the chroot and reinstall Grub there.

Step 1: Mounting the root and EFI partitions

mount $myroot /mnt
mount $myefi /mnt/boot/efi

Step 2: Preparation of further functions for the chroot environment

for i in dev dev/pts proc sys sys/firmware; do mount --bind /$i /mnt/$i; done
mount -o bind /etc/resolv.conf /mnt/etc/resolv.conf

Step 3: Change into chroot environment

chroot /mnt

Step 4: Update and reinstall the bootloader

apt-get --reinstall install grub-common grub-efi-amd64 os-prober
update-grub
grub-install

Step 5: Exit Chroot environment

Finally you can leave the chroot environment by typing exit twice and reboot the system with reboot. At the next start the boot manager Grub should appear again. If not, check the boot sequence in the BIOS again and change it if necessary.

Devices without UEFI

Step 1: Mount the root and the EFI partition

mount $myroot /mnt

Step 2: Preparing other functions for the chroot environment

for i in dev dev/pts proc sys sys/firmware; do mount --bind /$i /mnt/$i; done
mount -o bind /etc/resolv.conf /mnt/etc/resolv.conf

Step 3: Switch into the chroot environment

chroot /mnt

Step 4: Update and reinstall the bootloader

apt-get --reinstall install grub-common grub-efi-amd64 os-prober
update-grub

grub-install /dev/sdX

Step 5: Exit Chroot Environment

Finally you can leave the chroot environment by typing exit twice and reboot the system with reboot. At the next start the boot manager Grub should appear again. If not, check the boot sequence in the BIOS again and change it if necessary.