The problem is that Kobo change the strings returned by the device each time they update the f/w; they keep the USB ID the same, but now change the device description passed by USB to indicate the F/W level. See usr/local/Kobo/udev/usb
Code:
PARAMS="vendor=$VENDOR_ID product=$PRODUCT_ID vendor_id=Kobo product_id=eReader-$VERSION SN=$SN"
if [ "$ACTION" == "add" ]; then
sync
umount -l /mnt/onboard
umount -l /mnt/sd
/sbin/insmod /drivers/$PLATFORM/usb/gadget/arcotg_udc.ko
sleep 2
/sbin/insmod /drivers/$PLATFORM/usb/gadget/g_file_storage.ko file=$LUNS stall=1 removable=1 $PARAMS
sleep 1
It's not always been this way; I do recall that originally the version was not included here.