@ 57goldtop
I think you misunderstood the Firmware instructions. The S key isn't supposed to go into the bootmenu at all. It's supposed to disable the Cyberstorm's SCSI. The bootmenu described therein is the standard AmigaOS Early Startup Control.
Basically, you want to disable the onboard SCSI, boot with no startup-sequence, and run the Flash updater (put it on floppy). To be extremely safe, disconnect all your drives from the Cyberstorm, but that's probably overkill.
And make sure you're using
the latest LhA to extract the Flash update.