Hi Al,
Sorry I don't know the answer. We have been asked a few times but no one ever got back to us one way or the other. My guess is that it would work as we are only a Full Speed device which was supported by USB 1.1. The FTDI chip we use is very common so if another FTDI device works then KFLOP should as well.
If you want to do an experiment let us know.
Regards