There is one further possibility: I guess the SupraDrive is a HDD, right ? So if the guy who installed the HDD chose a higher boot priority for it than 5, then the Amiga will not even try to boot from floppy. The floppy drive's priority is 5 and the Kickstart always boots from the drive with the highest priority.
Also bootiing from df1..df3 with Kickstart 2.0+ only works if the HDD's boot priority is less than -3 because DF1 and prio -1, DF2 -2 and so on. Usually the HDD's prio is 0, so with a HDD attached it will only boot from DF0 if a disk is present.
Bye,
Thomas
