Thanks for the explanations!
It appears my Librem 14 has a random problem booting from USB, not really related to Clonezilla!
It happens with the PureOS Live 10 USB just the same.
I tried to boot from PureOs Live 10 disk a number of different ways but only once did it boot into the OS. I know it was actually the USB OS because it did not ask for the disk encryption nor the user password and started with the welcome screen for language selection.
But, following the exact same steps again results in an error message instead (see end of post for details)
At first I thought it might have to do with the Librem key in the other USB port, so I tried without it but got the same error message.
Then I swapped the PureOS Live 10 USB drive from right to left USB port, and that’s when it booted that one time.
Then I tried the Clonezilla USB drive in the left USB port, with and without Librem key, resulting in the same error message.
Then I tried again with the PureOS Live 10 USB in the left USB port - and now it is not working and showing the same error message.
Below is the error message ( I have not completely typed out the long ?hexadecimal? strings; they are always the same):
New value of PCR[4}: 69745da56385 etc etc etc 6d36
Scanning for USB storage devices…
mount: mounting /dev/sda on /media failed: No medium found
sh: o: unknown operand
!!! Something failed during USB boot
New value of PCR[4]: c7047 etc etc etc 995
!!! Starting recovery shell
~ # _
Any ideas anyone what is going wrong here?