Yes, that's a "raw" condition. Did the size for the "unallocated" show properly? Did you right clk on the unallocated area and choose "NEW"? What happened when you did that? Should get a sizing box with a choice of setting LABEL, the file system format you want, and the type of partition (logical or primary).
If you do this in Disk Manager in Windows, be sure to "initialize" the flashdrive first.
For the dd command in linux you check GParted to be sure of the drive designator, such as sdc or sdd, or sde, and so forth. You'd then run the following from terminal or console or Konsole.
dd if=/dev/zero of=/dev/sd*
where the * is the designator for that drive. I'd advise if you are unsure of doing this, unplug the data cable from your hard drive first, just to be safe. The command's name is "disk destroyer" because people often screw up the output file destination and end up wiping their hard drive instead. What that command does is write zeros over the entire drive. If there is some rootkit or boot sector virus on the flashdrive it will clear it. A faster approach if you think it's just a rootkit or virus is to overwrite just the MBR on the flashdrive.
dd if=/dev/zero of=/dev/sd* bs=1M count=2
which clears the first 2 MB on the flashdrive. Some clear only the MBR, but I figure since no data is at risk, a little overkill never hurt, also some flashdrives end up getting GPT on them and that takes more room than MBR and can crap up use of a flashdrive on some computers.