not that I am an expert but me thinks one might clone the usb stick onto another usb stick
and then attempt recovery from usb number 2
2) There are number of threads on usb sticks and whether or not to format it as journalised or NOT journalised
my personal view is to journalise as I accept usb sticks are cheap to buy.
----when they reach their write limit number....ditch it but
3) for my internal drive, which is journalised as ext4.....I use fsarchiver to "IMAGE" the partition
partimage can not handle (currently) ext4 but can handle ext3
but
fsarchiver is super fast....much faster than partimage....in both writing and restoring images.
so to the OP, if recovery fails I suggest you record the tool you use to format and partition (eg gparted)
the actual number you input.....whether they change to cylinder boundaries or not
------so you can always reproduce your table
b) make a backup of your MBR assuming you are don't have to use GPT
I will always use PRIMARY and never use LVM or extended partitions so
sudo dd if=/dev/sdx of=/pathway/mbr-backup bs=512 count=1
will be a backup, if you have more than one drive or usb stick to backup, rename mbr-backup to something more specific
change sdx to sda or sdb etc
c) once you have some data on your usb stick
use a second usb stick or internal drive to "image" the partition and then burn that image to a dvdrw
or send to cloud storage such as dropbox with its MBR
good luck
Of course specific files can be sent to cloud storage if not sensitive
NSA may have broken encryption so don't worry about it
http://www.itnews.com.au/News/355942,nsa-can-break-some-encryption-new-snowden-leak.aspx