Comment 2 for bug 536670

Interesting, it only seems to happen for VFAT, not for any other file system.

It seems likely that the bug is actually in libparted:

$ sudo /lib/udev/udisks-part-id /dev/sdb
device=0xe56e00' for devpath=/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-8/1-8.2/1-8.2:1.0/host13/target13:0:0/13:0:0:0/block/sdb
Expected `linear' in UDISKS_DM_TARGETS_TYPE=`(null)'
using device_file=/dev/sdb syspath=/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-8/1-8.2/1-8.2:1.0/host13/target13:0:0/13:0:0:0/block/sdb, offset=0 ao=0 and number=0 for /dev/sdb
Entering MS-DOS parser (offset=0, size=1028653056)
MSDOS_MAGIC found
looking at part 0 (offset 0, size 0, type 0x00)
new part entry
looking at part 1 (offset 0, size 0, type 0x00)
new part entry
looking at part 2 (offset 0, size 0, type 0x00)
new part entry
looking at part 3 (offset 0, size 0, type 0x00)
new part entry
Exiting MS-DOS parser
MSDOS partition table detected
UDISKS_PARTITION_TABLE=1
UDISKS_PARTITION_TABLE_SCHEME=mbr
UDISKS_PARTITION_TABLE_COUNT=0