How to backup (and restore) Persistent Kali Live USB

I'm just getting started with Kali, and for now I've chosen to run it from a Live USB which ive set up as persistent - no problems. Note that this is NOT encrypted.

My question is: How can I periodically (manually) backup the contents of the Live UBS stick? Is there a way to do a byte-for-byte backup of the whole stick ? or should I just intend to backup the contents of the 'persistence' partition ie not the ? can this be as simple as an archive of that partition (tar?)

Of course I would wish to restore the backup if the need arises - if I make a new live USB how can I be confident that the restored 'persistence' volume would work with that new stick?

BTW - My laptop has ubuntu installed, so I'd be backing up/restoring to that -- I guess that makes this a Linux question, but since my concern is the integrity of the Kali persistence volume - hence asking the question on a Kali forum ;)

thanks all.
Charlie

Interested in this too ... not a lot of detail available for backing up live usb with persistence.

Teejee Timeshift looks good ... but no detail as to whether it is suitable for live persistent usb ... check it out:

http://www.teejeetech.in/p/timeshift.html