This is the continuation of the post titled Recover Files From Bad Disk .
If, and only if, photorec cannot detect your bad disk... here another way... not as easy, but more useful
Of course, we will be using Linux again :D
Plug in your disk, wait for few seconds, then type 'mount' in terminal, and you will get an output like this:
We're looking for a FAT32 filesystem, the USB or SD disk... here, it will be denoted as 'vfat', short form of Very Fat (Hahahahaha). So, from the image above, my USB drive is /dev/sdb1 (see the 'type vfat' that is in the last entry? that's what we're looking for)
Now, unmount the disk by typing 'umount /dev/sdb1' (/dev/sdb1 is the example, from now on, replace it with the result of your 'mount' command that points to a vfat filesystem type)
Next, we're going to perform filesystem check. type 'sudo fsck -f /dev/sdb1'
And that's it. Bad sectors are checked are fixed... Now you can try to do testdisk as in this post again :)