16GB USB Drive Not Accessible

Phil Meyer pmeyer at themeyerfarm.com
Fri Oct 31 17:52:46 UTC 2008


Christopher A. Williams wrote:
> ...
>
> Now, one last question: what's the flag to format a FAT32 partition with
> mkfs? I saw options for pretty much everything but that. I'm probably
> just suffering from not having had my first cup of coffee... :)
>   


I deal with this often, as its part of my job to produce bootable pen 
drives and CF cards.  I like using pungi and revisor to roll a product 
specific distro, and using livecd tools for copying them to the pen drives.

Most of this is scripted for convenience, but all new drives go through 
a process like this:

Stomp on the MBR:

cat /usr/lib/syslinux/mbr.bin >/dev/${disc}

That particular file is a generic GPL MBR.  Its part of the syslinux rpm.

Run fdisk to delete all partitions and recreate just what is necessary 
-- the script for that is kinda hard to read unless you are intimate 
with fdisk, so I won't post it here to prevent confusion.

Be sure to tag the primary (assuming 1 here) partition as bootable.

Then to format:

mkfs -t vfat -F 32 -n "$name" /dev/${disc}1

Some vendors like to really mess with their thumb drives, requiring a 
bad sector check during format.  Add a -c to the above for that.  It 
takes a bit longer, but might help on a stubborn drive.

Good luck!





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