How to: Dualboot Windows +Bitlocker and Kubuntu +LUKS

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Preparation

Tested with

Tested with: Win 11 Pro 23H2, Kubuntu 24.04
Last Update: 2024-09-29

Environment

  • UEFI Notebook
  • Secure Boot enabled (should also work without)
  • NVMe disk /dev/nvme0n1

Steps

1. Create partitions

  • Boot Ubuntu live session from a pendrive.
  • Open gparted via “sudo gparted”
    • create new GPT partition table
    • create partition: 550MiB FAT32 labelled EFI
    • create partition: 550MiB EXT4
    • create partition: 103264 MiB NTFS (102500 + 764)
      My windows will be using 100 GB here. If you activate Bitlocker later on, 764 MB will be taken from this partition. If you need 200 GB for instance, you can take 205664 (204900 + 764).
    • apply changes
    • right click on EFI partition, manage flags, set BOOT and ESP

2. Install Windows

  • Boot Windows from pendrive and install into your NTFS partition above.
    (Keep in mind that only the Pro versions and above are supporting Bitlocker.)
  • Do not set up Bitlocker yet. On current Windows 11 installations Bitlocker is activated automatically. Turn it off: Settings > Privacy & Security > Device encryption > Device encryption > off

3. Install Kubuntu

  • Boot up Kubuntu live session
  • Select to try Kubuntu
  • Open the KDE Partition Manager while providing an empty passwort for authentication
    • create a new primary partition in the unallocated area for your Linux: 204800 MiB ext4 (/dev/nvme0n1p5), you can take as much as you need
    • apply and close
  • Run the installer icon on the desktop
    • Set up your location and keyboard layout
    • Choose to replace a partition, with ext4
    • Click directly on the partition you just added (nvme0n1p5) in the bottom row named „Current“
    • Click on encrypt system and provide a good passphrase
    • You will notice that the colors changed in the second bottom row named „After“. Your latest partition will be split up into „kubuntu_boot“ and „kubuntu_2404“.
    • Next, provide your name etc. and proceed with the installation.

Both systems can boot up properly now. You will be asked by GRUB which operating system to boot now: Ubuntu or Windows Boot Manager.

4. Activate Windows Bitlocker

  • Boot into Windows and look for Bitlocker in the settings. Go through the guided steps as you normally do, to achieve Bitlocker encryption.

Good to know

If you are not living in a region with timezone UTC, you will notice the system time differs between Windows and Ubuntu. To fix that simply issue “sudo timedatectl set-local-rtc 1” in the Ubuntu terminal. Once you set up your time correctly within Windows, your system time will not jump around any more.

Credits