stiahnes si napr. z http://www.bootdisk.com/bootdisk.htm zo sekcie
Non-Windows Based Image Files W/ImageApp kliknes na "Win98SE" to ti stiahne .zip subor a v nom mas .img subor (skus premenovat na .ima a dat to tvojmu programu namiesto diskety).

Tvoj program ma volbu vyrobit bootovatelny disk z diskety (prostredna sekcia, prva moznost z vrchu), tak mu skus namiesto fyzickej diskety dat obraz diskety (.ima).

Citujem z navodu k tomu tvojmu FlashBoot:

You may create plain bootable disk with minimal set of system files required only
for boot.
MS-DOS, PC-DOS and FreeDOS are supported. If you choose to use MS-DOS or
PC-DOS, you have to provide the source of DOS kernel files to FlashBoot. There are
may different cases supported: bootable DOS floppy disk or floppy disk image