Hi Zbigniew - Not familiar with the particular EMUF-720F device you mentioned, but there are many micro-controller based floppy disc emulators, and I use a couple with my older devices. Getting a floppy drive to appear bootable was usually done with jumpers on the circuit board. Is the old (non working?) drive available? How you did it varied by drive manufacturer. Some pictures of drive options are here: http://embeddedsw.net/EMUFDD_Floppy_Hardware_Emulator_Home.html#Jumpering The boot drive is usually DS0, but I have a system that will only boot from DS1, so there's no standard. Keeping old hardware running - especially solid old CNC machinery - is really important. If all else fails, I have sources for most old floppy drives and media, but they are getting rarer and less reliable every year. cheers, Stewart