First and foremost - encrypt your USB drives! Even if you think you have "nothing to hide" if you accidentally lose a USB thumb drive (it's easy to lose small objects) and it's not encrypted then potentially someone might be able to obtain enough information about you to commit identity fraud, take out loans, open bank accounts, etc. Use LUKS encryption. In Ubuntu you can do this using the Disk Utility application. Some instructions can be found here.

Insert a USB thumb drive into the front socket of the Beaglebone Black.

Log into the system and become the root user, then run the backup command.

ssh username@domainname -p 2222
su
backup

Type in the password for the USB drive, then if this is the first time that you've made a backup then you will be prompted for your GPG key passphrase.

When the backup ends remove the USB drive and keep it somewhere safe. Even if it gets lost or falls into the wrong hands the content is encrypted and so is unlikely to become a source of leaks.

Insert the USB thumb drive containing your backup into the front socket of the Beaglebone Black.

Log into the system and become the root user, then run the restore command.

ssh username@domainname -p 2222
su
restore

Enter the password for the USB drive, then you will be prompted to enter your GPG key passphrase. When the restore is complete you can remove the USB drive.

Distributed backups are a better way of ensuring the persistence of your data, such that even if your system gets stolen or destroyed then the data will still be recoverable from your friends. Since the backups are encrypted your friends (or anyone else with access to their systems) won't be able to read your backed up content even if their systems are subsequently compromised.

Firstly you will need to have a user account on one or more of your friends servers. They don't necessarily need to be using Freedombone, just some version of GNU/Linux with ssh access. They can create a user account for you with the adduser <username> command when logged in as root and then give you the username and password via a secure method, such as on paper or via an encrypted email or via an XMPP chat using OTR. Make sure that the password used is a strong one - preferably a long random string stored in a password manager - so that dictionary attacks will fail. Also for maximum resilience put your password manager file onto a USB thumb drive and carry it with you.

ssh username@domainname -p 2222
freedombone-remote

You can then enter the usernames, domains and ssh logins for one or more remote servers. The system will try to backup to these remote locations once per day.

Very important is to take a copy of the contents of backup.key.

su
cat /etc/ssl/private/backup.key

If the backup key doesn't yet exist then you can manually create it with:

freedombone-addcert -h backup

Store it within a password manager on a USB drive which you carry with you. In the worst case scenario you'll be able to restore your system on completely new hardware if you have this key, so long as at least one of your friends servers is accessable via ssh.