You should really get the proper A3000 3.1 Roms.
My A3000D's ROMS, when I got it, loaded the kickstart from the HDD, by holding down both mouse buttons at power on, you could select at a boot screen 1.3 or 2.0. Then it would boot to whichever you selected. You could also ask it to load from a floppy "Superkickstart Disk".
In experimenting with kickstarts, I found the only versions I could get to work, were A3000 only ROMS. Some bonus code is required by the roms it loads from disk. The bonus code may also be required by the real ROMS, I'm not completely sure.
A3000's need a pair of ROMS and can be hard to find, but I'm sure somebody here will know where to get em :-)
cheers... :pint: