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github-actions[bot] edited this page Apr 27, 2026 · 4 revisions

User tools & setup > Change default kernel

Contents

  1. Find kernel id with bootctl
  2. Edit boot loader config
  3. Verify and reboot
  4. Additional information

Overview

Your system can have multiple kernels (or installations) of the same Linux distro. This is typically from having different ISO images, such as EOS Mercury, Titan, and Ganymede. The newest kernel is usually booted by default, but can be adjusted to user preference.

To change the default kernel at system boot, you need to identify and adjust the kernel ids used in the boot loader config file.

Note

This guide is for systems using the default systemd-boot UEFI boot manager in Endeavour OS.

1. Find kernel id with bootctl

  1. Change to the root user with sudo -s and enter your password.

  2. Check which kernel is currently set as default with:

     $ bootctl list

  3. The terminal will display installed kernel information, indicating which kernel was (selected) at boot, and which one is set as (default).

    # kernel currently booted and set as default 
   type: Boot Loader Specification Type 1 (.conf)      
  title: EndeavourOS (6.19.11-arch1-1)  (default) (selected) # current
     id: 1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1.conf
 source: ...
sort-key: endeavouros-6.19.11-arch1-1
version: 6.19.11-arch1-1
machine-id: 1fcde8d015be4360aa122975ea19eca2 # current default id
  linux: ...
 initrd: ...
options: ...
    # kernel to set as default at boot
   type: Boot Loader Specification Type 1 (.conf) 
  title: EndeavourOS (6.19.12-arch1-1)
     id: af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1.conf
 source: ...
sort-key: endeavouros-6.19.12-arch1-1
version: 6.19.12-arch1-1
machine-id: af2ba735c1714a3ebdd24c10355d5b20 # id to set as default
 ```

  4. Copy the machine-id of the kernel you want to set as the default. In this example:

    • Current id: 1fcde8d015be4360aa122975ea19eca2
    • New id: af2ba735c1714a3ebdd24c10355d5b20

2. Edit boot loader config

  1. Enter nano /efi/loader/loader.conf to edit the boot loader config in the terminal.

    Terminal window showing the loader.conf file being edited with GNU nano editor

  2. On the line containing default, replace the old machine-id with the updated id.

  3. Add a wildcard/asterisk after the id (no space in between). This ensures the same kernel is booted regardless of release version, which can change after system updates.

      default af2ba735c1714a3ebdd24c10355d5b20* # add wildcard *
  timeout 20  # wait time (sec) before system boots default
  console-mode auto
  reboot-for-bitlocker 1

  4. Double check the kernel id you entered is an exact match with the one from bootctl list.

  5. Press Ctrl+X to finish editing, then press Y to save the updated config.

3. Verify and reboot

  1. Run bootctl list again to verify the desired kernel has (default) by the kernel title.

        type: Boot Loader Specification Type 1 (.conf) 
   title: EndeavourOS (6.19.12-arch1-1)  (default) # new default
      id: af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1.conf
  source: ...

  2. Reboot the system to check that the correct kernel boots by default.

4. Additional information

Useful resources:

Use ls to find kernel id

A list of the installed kernels can also be viewed with the ls command. This does not indicate which kernel is set to default, but has a much simpler terminal output.

  1. Enter ls /efi/loader/entries/ to display a list of the kernel entries.

     $ sudo ls /efi/loader/entries/
 1fcde8d015be4360aa122975ea19eca2-6.18.21-1-lts.conf	      1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1-fallback.conf
 1fcde8d015be4360aa122975ea19eca2-6.18.21-1-lts-fallback.conf  af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1.conf
 1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1.conf	      af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1-fallback.conf

  2. The kernel id is the identifying string in front of the version number.

     # kernel id                      # version number
 af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1.conf
 1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1.conf

  3. Enter ls -l /efi/loader/entries/ to list all kernel entries with last updated dates.

     $ sudo ls -l /efi/loader/entries/
 total 24
 -rw-r----- 1 root root 534 Apr  6 03:23 1fcde8d015be4360aa122975ea19eca2-6.18.21-1-lts.conf
 -rw-r----- 1 root root 565 Apr  6 03:23 1fcde8d015be4360aa122975ea19eca2-6.18.21-1-lts-fallback.conf
 -rw-r----- 1 root root 542 Apr  6 03:23 1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1.conf
 -rw-r----- 1 root root 573 Apr  6 03:23 1fcde8d015be4360aa122975ea19eca2-6.19.11-arch1-1-fallback.conf
 -rw-r----- 1 root root 542 Apr 20 18:18 af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1.conf
 -rw-r----- 1 root root 573 Apr 20 18:18 af2ba735c1714a3ebdd24c10355d5b20-6.19.12-arch1-1-fallback.conf

  4. In most cases, the (selected) kernel is likely the last updated file. In this case, it would be the entry accessed on Apr 20 18:18.

Note

While the ls -l does not provide exact details like bootctl list. The simplified output is useful as a quick overview of the kernels installed on your system.

Use cat to view boot config

While bootctl list provides detailed information on installed kernels, you can use cat to view the boot loader config file.

  1. Enter sudo cat /efi/loader/loader.conf to display the boot loader config.

     $ sudo cat /efi/loader/loader.conf
 default af2ba735c1714a3ebdd24c10355d5b20*  # kernel id
 timeout 20
 console-mode auto
 reboot-for-bitlocker 1

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