well it might have to boot off cdr. what you could do is put a orginal ps2 dvd game in your drive, and use isobuster to find out what LBA your SYSTEM.CNF and the file it calls are.
NOTEPAD D:\SYSTEM.CNF (replace D: with your dvdrom drive) In there will be a file it is pointing too that also resides in the same directory of the SYSTEM.CNF.
Actually, just open up isobuser, click over to the left and hit Copy Tree-Info to File, then just paste that here. keep in mind, i dont have a ps2 nor a ps2 game so i cant do this :-(