On my #Librem14 I'm running #PureBoot. Before my update to #PureOS Crimson (which is still in development) I needed to make sure I could recover to my old system.

get ready

Preparation for booting into a rescue system and recovering the files on /root and /boot:

• luks password for /root of notebook
• luks password for backup disk
• rescue system on usb-stick (I used the PureOS image)

pureboot

Reboot. After PureBoot showed the PCRs hit a key to enter the boot menu.

• remove the LibremKey that had been used to verify the firmware
• insert boot usb-stick (don't insert it beforehand: selecting the usb boot option from the menu will drop you to a rescue shell)
• if you end up in a rescue shell, disconnect the usb boot medium, reconnect it, check dmesg and if the medium has been found call usb-scan which will get you back to a usb boot menu showing boot entries for the usb boot medium

mount disks

Once booted to a rescue system connect the backup medium and unlock it when asked for the luks passphrase.

To unlock the /root partition of the Librem14 I used gnomes disk manager. In gnomes disk manager I also mounted the unlocked luks volume.

recover

Do whatever is necessary to recover the files from the backup to the internal harddisk.