Usb boot device totally unable to be formatted

Yeah, this is a pain in the butt and it caused me many head-aches too. I finally figured out how to get mine working again by doing the following.

First we're going to be using the terminal and the command dd. This can be dangerous so take it slow and double check everything. Triple check actually because this will delete everything on your usb key and it can delete everything on your computer if you mess this up.

First run:

sudo fdisk -l

This will show you the devices that are plugged into your computer. You want to find the name of the usb key you want to format. It will probably be sdb, BUT IT MAY NOT. Look for a device with two partitions and with the size of your usb key.

Next run:

sudo dd if=/dev/zero of=/dev/sdx

replace x with the letter of the usb key from the last command. We don't care about the numbers following that letter. Make sure you get this part right; otherwise you may kill your computer!

This will make your usb key all zero. This command will take some time to run.

Now use Gparted and format it to whatever you want. If it gives any error just click through it and try again until it does it.

This might be a controversial suggestion, but if all else fails I'd try formatting the USB using a Windows PC! I'm no Ubuntu expert, but I've had problems using GParted and other tools to format a USB stick after messing up the files on it. However, Windows always seems to somehow get the drive back to plain FAT32. Don't ask me why, it's just my personal experience.

Please bear in mind that this could very well be my limited knowledge of all the options GParted has to offer, rather than Windows doing a better job!