Restore Your USB Key to Original State via Terminal

Restoring your USB key to it's original state using Linux:

A. First we need to delete the old partitions that remain on the USB key.

1. Open a terminal and type sudo su
2. Type fdisk -l and note your USB drive letter.
3. Type fdisk /dev/sdx (replacing x with your drive letter)
4. Type d to proceed to delete a partition
5. Type 1 to select the 1st partition and press enter
6. Type d to proceed to delete another partition (fdisk should automatically select the second partition)

B. Next we need to create the new partition.

1. Type n to make a new partition
2. Type p to make this partition primary and press enter
3. Type 1 to make this the first partition and then press enter
   
4. Press enter to accept the default first cylinder
5. Press enter again to accept the default last cylinder
6. Type w to write the new partition information to the USB key
7. Type umount /dev/sdx (replacing x with your drive letter)

C. The last step is to create the fat filesystem.

1. Type mkfs.vfat -F 16 /dev/sdx1 (replacing x with your USB key drive letter)

That's it, you should now have a restored USB key with a single fat 16 partition that can be read from any computer.