i have made an image of a friends usb pen drive(their collage thesis is on it). it currently gives a message about a bad superblock when trying to mount the image or the pendrive. i used "dd if=/dev/sda of=usbdrive" to make the image.

as i understand, the superblock means the filesystem (pen drive is fat32). is it possible to overwrite these superblocks and mount the image i made? or is there any way to recover the files on it?

Fist try
and see if the files are under /mount/point/of/your/choice after that ("usbdrive" is now the image file, not the stick itself).

I think "superblock" means the beginning of the partition where the filesystem information is stored (partition table etc.) and that FAT32 actually should have two places where partition table is written, so that if the other one gets corrupted, the other one can be used instead. Don't know about that, but it sounds bad if the stick doesn't mount. Usually they either work or are completely trashed (I had one of my usb sticks, 512MB, simply cause an error while normally software-ejecting it, and now it shows 8MB, there's nothing and you can't actually write on it..)

Quote the exact error message please. Include the command used to mount.

Note, I would have expected

dd if=/dev/sda5 of=usbdisk
... to copy, and

mount -t vfat usbdisk /mnt/usbdisk -o loop
... to mount.

But why not just copy the files out? (Do you mean that the usb stick dosn't mount or that the image doesn't?)

thank you, ive tried to mount as you have said, but i just get that bad superblock error. i dont really care about the drive itself, id say its broken, im more interested in the data on it. i just thought if it was the partition tables that are corrupt i might be able to overwrite my image with some generic partition table to be able to mount it.

neither the drive or the image will mount. im in work at the moment so not by my pc but the error is something like "wrong fs type, bad option, bad superblock on /dev/sda"

Yeah, that sounds like the partition table (at least).
Note: your image is a faithful copy of the damaged partitions.
Best bet... try the dd command on the explicit partition (/dev/sda5) with the data on it. (USB sticks usually are preformatted with a single logical partition occupying the entire drive.)

Since what you really want is to recover the thesis, right, you can always grep through the dev for the thesis text the old fashioned way. Or use recovery software... you have a backup, so how about fsck run on the drive. Or use one of the many Linux Forensics software collections.