If you have a buddy with the sd card you want to duplicate, the following command (Linux, Mac OS X, Cygwin, Win 10 bash shell, ...) should allow you to make an exact bit-by-bit duplicate of one sd card onto another sd card (of the same size) regardless of the format used.
Be extra careful that you have input and output devices correctly identified or you will wipe out the good card by writing the bad card to the good card.
if - is the input block device
of - is the output block device
bs - is the block size (in this case 100 MB)
conv - is the conversion to apply to the copy
# dd if=/dev/sda of=/dev/sdb bs=100M conv=notrunc
Oh, and the # prompt means that you will have su'd to root or sudo'd the command. If you don't know what this means and are not comfortable with it, then don't try this and use another solution.
Review the dd man page for options available to you and be careful with commands like this - they can be catastrophic. You have been warned multiple times!
You probably should have used this method to make a backup of your OEM card prior to attempting any modifications. Just sayin...