mikey:~ # view /proc/bus/usb/devices

T:  Bus=04 Lev=01 Prnt=01 Port=02 Cnt=01 Dev#=  2 Spd=480 MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=14af ProdID=af01 Rev=11.00
S:  Manufacturer=SAMSUNG
S:  Product=SAMSUNG SUM-2G
S:  SerialNumber=0190107060001334
C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA
I:  If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=31875us

My machine sees the device but if I try and mount it.

mikey:~ # mkdir /mnt/usb
mikey:~ # mount -t vfat /dev/sda1 /mnt/usb/
mount: /dev/sda1 is not a valid block device

Now lets see what fdisk says.

mikey:~ # fdisk -l

Disk /dev/hda: 80.0 GB, 80032038912 bytes
255 heads, 63 sectors/track, 9730 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/hda1               1         131     1052226   82  Linux swap
/dev/hda2             132        9729    77095935   83  Linux

Disk /dev/sda: 2030 MB, 2030043136 bytes
255 heads, 63 sectors/track, 246 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1         247     1982463+  ee  EFI GPT
Partition 1 has different physical/logical beginnings (non-Linux?):
phys=(1023, 254, 63) logical=(0, 0, 2)
Partition 1 has different physical/logical endings:
phys=(1023, 254, 63) logical=(246, 205, 23)
The problem is the first (non-Linux?) physical partition.  To fix it I need to delete the partitions and recreate them.  Now I know my device isn’t mounted but just to make sure.

mikey:~ # umount /dev/sda1
umount: /dev/sda1: not mounted

mikey:~ # fdisk /dev/sda

Command (m for help): d
Selected partition 1

Command (m for help): n
Command action
e   extended
p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-246, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-246, default 246): +750M

Command (m for help): a
Partition number (1-4): 1

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 6
Changed system type of partition 1 to 6 (FAT16)

Command (m for help): n
Command action
e   extended
p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (93-246, default 93):
Using default value 93
Last cylinder or +size or +sizeM or +sizeK (93-246, default 246):
Using default value 246

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
mikey:~ # mkfs.vfat -F 16 -n rhboot /dev/sda1
mkfs.vfat 2.10 (22 Sep 2003)

mikey:~ # mkfs.ext2 -b 4096 -L casper -rw /dev/sdb2
mke2fs 1.38 (30-Jun-2005)
Filesystem label=casper
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
154880 inodes, 309251 blocks
15462 blocks (5.00%) reserved for the super user
First data block=0
10 block groups
32768 blocks per group, 32768 fragments per group
15488 inodes per group
Superblock backups stored on blocks:
32768, 65536, 98304, 131072, 163840, 196608, 229376, 262144, 294912

Writing inode tables: done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

mikey:~ # mount /dev/sda1 /mnt/usb/

mikey:~ # dd if=/root/diskboot.img of=/dev/sda1
12288+0 records in
12288+0 records out

mikey:~ # fdisk /dev/sda

Command (m for help): p

Disk /dev/sda: 2030 MB, 2030043136 bytes
255 heads, 63 sectors/track, 246 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          92      738958+   6  FAT16
/dev/sda2              93         246     1237005   83  Linux

Now windows and Linux can read/write to my flash drive.