This guide describes Ubuntu-specific details of the Multi-boot Clear Linux* OS with other operating systems tutorial.

  1. Start the Ubuntu installer and follow the prompts.

  2. At the Installation type screen, choose Something else. See Figure 1.


    Figure 1: Ubuntu: Installation type.

  3. Create a new root partition.

    1. Under the Device column, select free space. See Figure 2.


      Figure 2: Ubuntu: Add partition.

    2. Click the + button on the lower left corner.

    3. Enter the new partition size. For this example, we used 40000 MB, as shown in Figure 3.


      Figure 3: Ubuntu: Configure new root partition.

    4. Set Use as to Ext4 journaling file system.

    5. Set the Mount point to /.

    6. Click OK.

    7. Under the Format? column, select the new partition to be formatted, in this example /dev/sda8.

  4. Share the swap partition that was created by Clear Linux OS.

    1. Under the Device column, select /dev/sda2.

    2. Click Change.

    3. Confirm Use as is set to swap area. See Figure 4.


      Figure 4: Ubuntu: Set swap partition.

  5. Follow the remaining prompts to complete the Ubuntu installation.

  6. At this point, you cannot boot Clear Linux OS because Grub is the default boot loader. Follow these steps to make the Clear Linux OS Systemd-Boot the default boot loader and add Ubuntu as a boot option:

    1. Boot into Ubuntu.

    2. Log in.

    3. Locate the Ubuntu grub.cfg file in the /boot/grub/ directory and look for the menuentry section. In Figure 5, the highlighted lines identify the kernel, the initrd files, the root partition UUID, and the additional parameters used. Use this information to create a new Systemd-Boot entry for Ubuntu.


      Figure 5: Ubuntu: grub.cfg file.

    4. Copy the kernel and the initrd file to the EFI partition.

      sudo cp /boot/vmlinuz-4.8.0-36-generic.efi.signed /boot/efi
      sudo cp /boot/initrd.img-4.8.0-36-generic /boot/efi
    5. Create a boot entry for Ubuntu. At a minimum, the file must contain these settings:

      Setting Description
      title Text to show in the boot menu
      linux Linux kernel image
      initrd initramfs image
      options Options to pass to the EFI program or kernel boot parameters

      See the systemd boot loader documentation for additional details.

      The options parameters must specify the root partition UUID and any additional parameters that Ubuntu requires.


      The root partition UUID used below is unique to this example.

      sudoedit /boot/efi/loader/entries/ubuntu.conf

      Add the following lines to the ubuntu.conf file:

      title Ubuntu 16.04 LTS Desktop
      linux /vmlinuz-4.8.0-36-generic.efi.signed
      initrd /initrd.img-4.8.0-36-generic
      options root=UUID=17f0aa66-3467-4f99-b92c-8b2cea1045aa ro
  7. Re-install Systemd-Boot to make it the default boot loader.

    sudo bootctl install --path /boot/efi


    If an older version of Ubuntu does not have the bootctl command, skip this step and see Restore the Clear Linux* OS boot loader to restore Systemd-Boot.

  8. Reboot.

If you want to install other OSes, refer to Multi-boot Clear Linux* OS with other operating systems for details.