[Coco] mb.floppy not functioning under the new sdc build

[K. Pruitt]

The mb.floppy script no longer functions correctly on the new nightly build 
supporting the sdc.  It generates an error 208 of all things when trying to 
format the destination disk.  Others errors follow.  This script worked fine 
previously.  The shell and something else are not playing well together as 
they once were.
This is on a stock, 100% unmodified version of the nightly build.  I figure 
if nothing else, this is a clue to the underlying problem so I'm passing it 
along.