Enabling the Boot Menu During Boot

If the VM is booting “hands-off” (i.e., the boot menu does not appear during boot), you can enable the boot menu by modifying the bootloader configuration. The steps depend on whether the system is using GRUB (for BIOS or UEFI) or systemd-boot (for UEFI).

Step 1: Determine the Bootloader

Follow the steps in the previous section to determine whether the system is using GRUB or systemd-boot.

Step 2: Enable the Boot Menu

For GRUB (BIOS or UEFI)

  1. Edit the GRUB configuration file:

    sudo nano /etc/default/grub

  2. Modify the following parameters to ensure the boot menu appears:

    • Set GRUB_TIMEOUT to a value greater than 0 (e.g., GRUB_TIMEOUT=5) to display the menu for 5 seconds.

    • Ensure GRUB_HIDDEN_TIMEOUT is either commented out or set to 0.

    • Set GRUB_TIMEOUT_STYLE to menu to always show the menu.

    Example configuration:

    GRUB_TIMEOUT=5
GRUB_HIDDEN_TIMEOUT=0
GRUB_TIMEOUT_STYLE=menu

  3. Save the file and regenerate the GRUB configuration:

    sudo grub2-mkconfig -o /boot/grub2/grub.cfg

  4. Reboot the system. The GRUB boot menu should now appear during boot.

For systemd-boot (UEFI)

  1. Edit the systemd-boot configuration file:

    sudo nano /boot/loader/loader.conf

  2. Add or modify the following parameters to ensure the boot menu appears:

    • Set timeout to a value greater than 0 (e.g., timeout 5) to display the menu for 5 seconds.

    • Set console-mode to auto or a specific resolution if needed.

    Example configuration:

    timeout 5
console-mode auto

  3. Save the file and reboot the system. The systemd-boot menu should now appear during boot.

Step 3: Temporarily Access the Boot Menu

If you only need to access the boot menu once (e.g., for testing), you can interrupt the boot process:

  • For GRUB: Press Shift (for BIOS) or Esc (for UEFI) during boot to bring up the menu.

  • For systemd-boot: Press Space during boot to bring up the menu.

Step 4: Verify the Changes

After making the changes, reboot the system and verify that the boot menu appears. If the menu does not appear, double-check the configuration files and ensure the correct bootloader is being used.

Summary

  1. Determine the bootloader (GRUB or systemd-boot).

  2. Modify the configuration file to enable the boot menu:

    • For GRUB: Edit /etc/default/grub and regenerate grub.cfg.

    • For systemd-boot: Edit /boot/loader/loader.conf.

  3. Reboot the system and verify the boot menu appears.

Note: The boot menu operates independently of wether the system is running in graphical mode or text mode, so the absence of an X server does not affect this process.