Formatting USB memory devices

Kevin O'Gorman kogorman at
Sun Apr 29 18:36:54 UTC 2012

On Sun, Apr 29, 2012 at 10:54 AM, Graham Watkins
< at> wrote:
> On 28/04/12 22:25, David Fletcher wrote:
> This was easy enough to do with Maverick.
> I've got a CF card plugged into a USB reader/writer that I want to
> format. The only application I can find that's supposed to do this is
> gnome-format but I can't get it to do anything, or even start up and
> show itself.
> How can I do this in 12.04 ?
> Dave
> The following is pasted from I've used this method
> before. Assuming that fdisk -l shows your card to be sdx,  there's no reason
> why it shouldn't work for you.
> 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.
>     Open a terminal and type sudo su
>     Type fdisk -l and note your USB drive letter.
>     Type fdisk /dev/sdx (replacing x with your drive letter)
>     Type d to proceed to delete a partition
>     Type 1 to select the 1st partition and press enter
>     Type d to proceed to delete another partition (fdisk should
> automatically select the second partition)
> B. Next we need to create the new partition.
>     Type n to make a new partition
>     Type p to make this partition primary and press enter
>     Type 1 to make this the first partition and then press enter
>     Press enter to accept the default first cylinder
>     Press enter again to accept the default last cylinder
>     Type w to write the new partition information to the USB key
>     Type umount /dev/sdx1 (replacing x with your drive letter)
> C. The last step is to create the fat filesystem.
>     Type mkfs.vfat -F 32 /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 32
> partition that can be read from any computer.
> It's always worked for me,

I believe you, but this is not *quite* the original state.  For that
you need to set the partition type in fdisk (the 't' command) to be
some M$ type, like 'c'.  Other types are possible for small drives,
but there's not much point.

By default, fdisk will have created the partition with a Linux type,
probably 83 unless your fdisk is *very* old and sets it to 81.

Kevin O'Gorman, PhD

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