USB Floppy drive seems to work quite fine, but there is some difference comparing with tradional Floppy drive. USB Floppy drive is identifying as mass storage like /dev/sdb (not /dev/fd0). If running some dd commands for example, the right path is /dev/sdx , where x=drive´s letter.

A practical example: Slitaz floppy-grub4dos image to the floppy using dd.
1. Find the drive
sudo apt-get install ufiformat
sudo ufiformat --inquire --verbose

… Floppy drive was /dev/sdb
list usb fdd devices
disk generic
/dev/sdb /dev/sg2

2. Image to the floppy
sudo dd if=floppy-grub4dos of=/dev/sdb

To mount floppy drive
sudo mount /dev/sdb /media/floppy

WorPress shows the commands wrong so read the right commands here