Install an OS with PureBoot configured#

Note

This guide assumes that you have set up the GPG keys with PureBoot.

Installing an OS with PureBoot configured with GPG keys may emit warnings about modified boot files or missing TOTP or HOTP counters. This guide will instruct you on how to address these warnings.

Compatibility#

PureBoot requires an unencrypted /boot partition.

Installing OS#

  1. From the PureBoot main menu, select Options.

    Screenshot of the PureBoot main menu
  2. Select Boot Options.

    Screenshot of the PureBoot options menu
  3. Select USB boot.

    Screenshot of the PureBoot boot options menu
  4. Select the USB device with the OS installation media.

  5. Proceed to install the OS.

Post OS Installation#

Take ownership of the TPM#

PureBoot keeps TPM and HOTP rollback counters under the /boot partition. Since the OS is just installed, these do not exist and they need to be created.

  1. Ensure your USB security token (Librem Key) is plugged in.

  2. From the PureBoot main menu, select Options.

    Screenshot of the PureBoot main menu
  3. Select TPM/TOTP/HOTP Options.

    Screenshot of the PureBoot options menu
  4. Select Reset the TPM. A confirmation prompt will appear and select “Yes”.

    Screenshot of the PureBoot TPM/TOTP/HOTP options menu
  5. PureBoot will temporarily drop to the console. You will be prompted to enter your USB security token admin PIN.

  6. The TPM and HOTP counter are now configured.

Signing /boot content#

Now that the firmware state is saved to the TPM and proven through the TOTP/HOTP, it is time to sign the /boot content.

  1. Ensure your USB security token (Librem Key) is plugged in.

  2. From the PureBoot main menu, select Options.

    Screenshot of the PureBoot main menu
  3. Select Update checksums and sign all files in /boot.

    Screenshot of the PureBoot options menu

Setting a new boot default#

  1. From the PureBoot main menu, select Options.

    Screenshot of the PureBoot main menu
  2. Select Boot Options.

    Screenshot of the PureBoot options menu
  3. Show OS boot menu.

    Screenshot of the PureBoot boot options menu
  4. Select a new boot option. A confirmation prompt will appear and you can choose to make it the default boot option.

    Screenshot of the PureBoot default boot confirmation
  5. If you choose to select a new boot option, PureBoot will ask you to re-sign the /boot content by asking for your USB security token user PIN.