[SoaS] add dd command use to backup a USB stick to .img file in floss manual section on backing up

[Martin Dengler]

----- Original message -----
> David;
>
> Here is a Backup Method that works for USB/SD sticks:
> (can you add this to Floss Manual as a backup method)
>
> do this outside of sugar:
> ------------------------------------------------------
>
> How to backup an installed live USB via a .img file
...
> Great fast backup

It is, indeed.  It's worth highlighting this is a backup method, not a duplicate-SoaS method (unless of course one uses it on a un-booted SoaS "stick").  I've noticed confusion between the two before.

> Tom Gilliard
> satellit