In general, it's recommended to only use official PS2 BIOS files and to follow proper procedures when updating or modifying the BIOS on a PS2 console.
DO YOU KNOW WHAT A GHOST WANTS?
: This specific version (part of the 9000x "Slim" family) is unique because it includes hardware changes that effectively patched out Free McBoot (FMCB) all ps2 bios files -including the new scph-90006-