Getting Started: Bootware 1.2

Quickstart - Download, Install, and Configure Bootware

In this Getting Started guide we describe how to bring up a common use case for Bootware - A/B partitioning for fallback and recovery.

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Supported Platforms and Operating Systems

The following matrix of platforms and Operating Systems support Bootware 1.2:

It is highly recommended to use a Pi with at least 4GB of RAM. Bootware requires approximately 700MB of RAM overhead for image verification and encryption. For HTTPS endpoints, the image must be 700MB smaller than your total RAM.

The default SCM/SEN as shipped has Zymbit software pre-installed. For setups using the ZYMKEY4 or other Zymbit HSMs, the installation is up to the user. The Zymbit product should be up and running with the blue LED flashing once every three seconds before installing Bootware. We recommend partitioning your /boot partition with a size of 512MB (default for Bookworm). There is no need to setup encryption of your root filesystem as Bootware will do this for you.

An HDMI console is highly recommended for setting up your unit with Bootware. The process of repartitioning and loading takes time and the console is handy for monitoring progress.

Bootware 1.2 includes a new, consolidated user interface. The process of installation and configuration has changed since 1.1.

Details of the commands in this Quickstart are linked in-line. See the Features section for more information on how to use Bootware.

Overview of steps to get up and running

You must have the Zymbit SCM/HSM and libraries successfully installed before installing Bootware. The blue LED should blink once every three seconds.

1. Download the Bootware management tool, zbcli.
2. Run zbcli install to install Bootware.
3. Run zbcli imager to create and sign a Zymbit image file (zi image) of your current root file system as a backup.
4. Run zbcli update-config to configure Partitions and Recovery strategy. For this Quickstart, we will setup A/B partitions.
5. Run zbcli update to load a known-good example zi image into the Backup (B) partition; set B to the Active partition.
6. Run zbcli rollback-swap to force a Rollback to your original partition to verify your A/B setup is working.

1. Download Bootware

A bootstrap utility to detect and load the correct build of Bootware can be downloaded with curl:

curl -sSf https://raw.githubusercontent.com/zymbit-applications/zb-bin/main/install.sh | sudo bash

The install will identify your Pi and OS and then prompt you if you’d like to include hardware signing. The SCM and HSM6 support hardware signing. All Zymbit products support software signing. For the purpose of this tutorial, we will use software signing. Use the arrow keys to move the selection to > No.

zb-install.sh: bootstrapping the zbcli installer
        ---------
        Pi Module:         Raspberry Pi 4/Compute Module 4
        Operating System:  Rpi-Bookworm
        Zymbit module:     Secure Compute Module
        Kernel:            kernel8.img
        ---------

? 'zbcli' comes with software signing by default. Include hardware signing? ›
  Yes
❯ No

Next, you will be asked to select a version of the zbcli from a list of recent versions to install. In most cases, you will want to select the latest version. Use the up and down arrows to select the version. You can use Ctrl-C to exit at any time.

? Select version ›
  zbcli-1.2.0-rc.25
  zbcli-1.2.0-rc.24
  zbcli-1.2.0-rc.23

2. Run zbcli install

Install Bootware. Answer yes when prompted to complete the installation.

sudo zbcli install

After installing the Bootware tools and artifacts, you will need to reboot into zboot. You will be prompted for confirmation to reboot.

? Bootware installation will require 62.59 MiB in `/boot/firmware` and will modify config.txt and rc.local. The system will be configured to boot from U-Boot. No system data will be lost.
       Found kernel '/boot/firmware/kernel8.img'
     Created '/etc/zymbit/zboot/mnt'
     Created '/etc/zymbit/zboot/scripts'
     Created '/etc/zymbit/zboot/zboot_backup'
     Created '/boot/firmware/zboot_bkup'
   Installed 'u-boot-tools'
     Created '/etc/fw_env.config'
     Created '/usr/bin/zb_get_root_dev.sh'
     Created '/usr/bin/zbconfig'
       Found OpenSSL 3
     Created '/boot/firmware/zb_config.enc'
    Modified zbconfig 'kernel_filename'
   Installed zboot
    Modified '/etc/rc.local'
     Created '/lib/cryptsetup/scripts/zk_get_shared_key'
    Modified '/boot/firmware/config.txt'
     Created '/etc/update-motd.d/01-zymbit-fallback-message'
    Modified /etc/update-motd.d/01-zymbit-fallback-message
? A reboot into zboot is required. Reboot now? (y/n) › yes

Reboot to complete the installation process and to boot through zboot. Once completed, all necessary files required for loading new images via Bootware will be installed.

3. Run zbcli imager to create a Bootware-ready Zymbit Image backup (zi image)

Bootware requires images in a secure, signed format for loading with zboot. We refer to these images as “zi images.” An image conversion tool, zbcli imager, creates the zi image. zbcli imager can take a snapshot of your running system or read from tarballs of your bootfs and rootfs partitions. Images can also be partial file additions and deletions called Overlay images.

If you are Developing on a CM4 directly and need to transition to an SCM, See Developing on the CM4 for instructions on how to create an image from your CM4 to load onto the SCM.

Create a zi image backup from your current running root file system

Use zbcli imager to create a zi image backup of your current system. Once created, the zi image can be propagated to other disk partitions securely. A private/public key pair will be used for signing the zi image at time of creation and verifying during the update process. Key pairs can either be created in software or using the Zymbit HSM hardware. For this Quickstart, we will use software keys. Details on signing and verifying can be found here.

In this guide, we will output the image directly to a USB stick. Mount the USB stick for access,

sudo mount /dev/sda1 /mnt

Start the imager module of zbcli. We will run interactively. You can also run non-interactively by supplying all necessary parameters on the command line. See zbcli imager for details.

All necessary information will be prompted for starting with the output directory and the name of the image file. The output directory will be excluded from the image. A .zi extension will be added to the image name provided.

sudo zbcli imager

   Validated bootware installation
        ---------
        Pi Module         Raspberry Pi 4
        Operating System  Rpi-Bookworm
        Zymbit module     Secure Compute Module
        Kernel            kernel8.img
        ---------
     Cleaned '/etc/zymbit/zboot/update_artifacts/tmp'
✔ Enter output directory · /mnt
✔ Enter image name · my_image

Next, you will be prompted for what type of image to make: A full image of the live system or an Overlay image from files added with zbcli manifest. An Overlay image can be used to add, replace, or delete a select group of files for updates, patches, etc. For this example, we will create a complete image from the running system. Select the Full Image option.

? Select image type ›
❯ Full image of live system
  Overlay image from files added with zbcli manifest

You can optionally provide an image version. This is for your use in helping to identify the image later. It is not used in the process.

Next, you will be prompted for signing keys. Keys can be Software or Hardware based and are used for signing and verification of images. Software keys are supported on all Zymbit products. Hardware keys are supported with Secure Compute Module (SCM) or HSM6 products. Had we chosen earlier to include hardware key support, we would be asked to choose either hardware or software key support. We chose earlier to not include hardware key support. You can use an existing key or instruct the imager to create new ones for you. For this Quickstart, we will generate a new Software key. Select Create new software key

? Select key slot ›
❯ Create new software key
  Use pre-existing software key

The imager will now build your zi image. Progress will be shown on the screen.

   Validated bootware installation
        ---------
        Pi Module         Raspberry Pi 4
        Operating System  Rpi-Bookworm
        Zymbit module     Secure Compute Module
        Kernel            kernel8.img
        ---------
     Cleaned '/etc/zymbit/zboot/update_artifacts/tmp'
✔ Enter output directory · /mnt
✔ Enter image name · my_image
✔ Select image type · Full image of live system
✔ (Optional) enter image version ·
✔ Select key slot · Create new software key slot
     Created signing key
    Verified path unmounted '/etc/zymbit/zboot/mnt'
     Cleaned '/etc/zymbit/zboot/mnt'
    Verified disk size (required: 3.97 GiB, free: 8.31 GiB)
     Created initramfs
     Running [====>                                   ] 1/10 (00:04:47): taking snapshot of boot             

The imager may take some time, depending on the size of your file system. Progress will be reported on the screen. Once completed, the zi image and private/public key will be saved to your specified output directory (/mnt). Keep your private key private. The zi image can be used from the local storage device or a remote server accessible via HTTPS. The public key file will be needed to load the zi image.

When complete, there will be three files in your output folder: the public key, the private key, and the zi image.

     ...

     Created signing key
     Created '/etc/zymbit/zboot/update_artifacts/file_manifest'
     Created '/etc/zymbit/zboot/update_artifacts/file_deletions'
    Verified path unmounted '/etc/zymbit/zboot/mnt'
     Cleaned '/etc/zymbit/zboot/mnt'
     Deleted '/etc/crypttab'
    Verified disk size (required: 2.54 GiB, free: 10.05 GiB)
     Created initramfs
     Created snapshot of boot (/etc/zymbit/zboot/update_artifacts/tmp/.tmpEyFuyt/my_image_boot.tar)
     Created snapshot of root (/etc/zymbit/zboot/update_artifacts/tmp/.tmpEyFuyt/my_image_rfs.tar)
    Verified boot tarball (/etc/zymbit/zboot/update_artifacts/tmp/.tmpEyFuyt/my_image_boot.tar)
    Verified zymbit and zboot tool installation
     Created staging directory (/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk)
     Created '/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/header.txt'
     Created tarball (/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/update_artifact.tar)
     Created header signature
     Created update artifact signature
     Created file manifest signature
     Created file deletions signature
     Created '/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/signatures'
     Created signatures (/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/signatures)
      Copied file (/etc/zymbit/zboot/update_artifacts/file_manifest) to (/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/file_manifest)
      Copied file (/etc/zymbit/zboot/update_artifacts/file_deletions) to (/etc/zymbit/zboot/update_artifacts/tmp/.tmpmwFylk/file_deletions)
     Created tarball (/mnt/my_image.zi)
     Created '/mnt/my_image_private_key.pem'
       Saved private key '/mnt/my_image_private_key.pem'
     Created '/mnt/my_image_pub_key.pem'
       Saved public key '/mnt/my_image_pub_key.pem'
       Saved image '/mnt/my_image.zi' (2.54 GiB)
    Finished in 894.5s
$ ls -l /mnt
total 1134224
-rwxr-xr-x 1 root root        242 Sep  8 11:55 my_image_private_key.pem
-rwxr-xr-x 1 root root        178 Sep  8 11:55 my_image_pub_key.pem
-rwxr-xr-x 1 root root 1161410560 Sep  8 11:55 my_image.zi

Additional examples of zbcli imager usage can be found here: zbcli imager usage

4. Run zbcli update-config to configure the Partitioning and Image loading

Now we will use the zi image and public key we just created to configure an A/B partition and load the image into the BACKUP (B) partition.

First, copy the public key file created earlier by the imager from /dev/sda1 to a location on your local filesystem.

cp /mnt/my_image_pub_key.pem .

Use the Bootware zbcli update-config to Configure your System

Bootware includes a tool to help configure your system called zbcli update-config. zbcli update-config is meant to setup your device environment to load a zi image from a configured endpoint, as well as choose an update policy for how to apply zi images. More information on zbcli update-config can be found here. Navigate through the menus with up and down arrows. Use ENTER to make a choice. Each configuration option will display the available options with explanations.

We are going to set a configuration with A/B partitioning that will UPDATE the BACKUP, leaving the A partition as the stable partition for fallback.

sudo zbcli update-config

   Validated bootware installation
        ---------
        Pi Module         Raspberry Pi 4
        Operating System  Rpi-Bookworm
        Zymbit module     Secure Compute Module
        Kernel            kernel8.img
        ---------
❯ Configure partition layout
  Configure update policy
  Configure update endpoint
  Configure wireless network
  Revert to default configuration
  Save and exit

Choose your settings as described below.

For Configure partition layout, choose [RECOMMENDED] A/B:

❯   [RECOMMENDED] A/B: This will take the remaining disk space available after the boot partition and create two encrypted partitions, each taking up half of the remaining space. Most useful for rollback and recovery with an Active/Backup configuration.

For Configure update policy, choose [RECOMMENDED] BACKUP:

❯   [RECOMMENDED] BACKUP: Applies new updates to current backup filesystem and swap to booting the new updated backup partition as the active partition now. If the new update is bad, it will rollback into the previous stable active partition.

For Configure data partition size in MB, choose the size of the encrypted shared DATA partition. The default is 512MB.

? Enter size of data partition in MB ›  1024

For Configure update endpoint, choose the block device that holds your zi image file.

       Using update endpoint '/dev/sda1'
  Defaulting to configured endpoint '/dev/sda1'
        Info update endpoints can be either an HTTPS URL or an external mass storage device like a USB stick.
? Enter update endpoint › /dev/sda1     

zbcli update-config will attempt to verify the zi image name if the endpoint is reachable.

Configure wireless network - Along with local devices, such as a USB stick, Bootware supports pulling remote updates via Wi-Fi or LAN connections. Wi-Fi credentials need to be provided in order for bootware to access the wifi during updates. If no wireless credentials are provided, the wireless interface is disabled in zboot.

Save and exit to save and exit zbcli update-config. You can Ctrl-C at any point before saving to exit the configurator without applying any changes.

5. Run zbcli update to create the Backup partition and load the zi image.

Once you are satisfied with your Bootware configuration, run zbcli update to complete the process of repartitioning and loading your image.

sudo zbcli update

   Validated bootware installation
        ---------
        Pi Module         Raspberry Pi 4
        Operating System  Rpi-Bookworm
        Zymbit module     Secure Compute Module
        Kernel            kernel8.img
        ---------
     Cleaned '/etc/zymbit/zboot/update_artifacts/tmp'
       Found update configs
? Proceed with current configs? These can be modified through 'sudo zbcli update-config'
        ---------
        Update endpoint   /dev/sda1
        Update name       my_image
        Endpoint type     LOCAL
        Partition layout  A/B
        Update policy     UPDATE_BACKUP
        ---------
 (y/n) › yes

The script will show your configuration for review and confirmation and give you the option to change the configuration. If not correct, enter no to exit. You may then re-run zbcli update-config to correct the configuration. If the configuration is not valid, zbcli update will exit.

Next, you need to enter the path to your public key file (in PEM format). For this example, we will use the public key file we copied locally earlier.

✔ Enter public key file (Pem format) · ./my_image_pub_key.pem

If verification with the Public Key succeeds, zbcli update will continue with progress information, then prompt for a reboot to complete the process.

Bootware Boot Process

The Bootware update process will now take place. Upon reboot in UPDATE_BACKUP mode, zboot will allocate, create, and encrypt a B partition, then load the contents of your zi image onto it. The A partition will remain untouched, and the system will come back online with partition B (cryptrfs_B) as its root filesystem.

If your original partition was more than half the available disk space and you were switched to UPDATE_BOTH during configuration, both A and B will have been created and your image loaded into both. In this case, the system will come back online after the update with its root filesystem on partition A (cryptrfs_A).

On the console, you will see:

• “Loading: Encrypted zboot please wait…” message, which takes around 4-5min.
• The A/B partitions will be configured and setup for LUKS encryption protected by the Zymbit HSM.
• It will then take a few minutes to process and validate the image.
• Depending on the size of the zi image, it may take a significant amount of time to load its contents into the root partition(s) being targeted for update.
• Once zboot is done unpacking the image to the B partition, it will boot your system with the B (UPDATE_BACKUP mode) / A (UPDATE_BOTH mode) partition as the ACTIVE partition. You can use lsblk to examine the partition layout.

4. Quickcheck: Manual Rollback (Active/Backup partitions)

To verify you now have two valid partitions, manually trigger a rollover from Active to Backup with zbcli rollback-swap. This will reboot your system into its non-active root partition. No update process will be invoked and the contents of both partitions will remain enchanged.

sudo zbcli rollback-swap

Once again, you can use lsblk to verify the active partition has changed. You should now have identical Active and Backup partitions with working images ready for your development.

If Bootware detects that the system has failed to reach a systemd init target for 3 consecutive attempts in a row, it will automatically initiate a rollback-swap of the root partitions upon the next reboot.

Additional Information and Support

zbcli commands

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