When working with PS2 BIOS files, especially if you're looking to flash a new BIOS or modify an existing one, it's essential to proceed with caution. Incorrectly flashing a BIOS can render your PS2 inoperable.
This is the oldest Japanese BIOS. It is known to have significant glitches and poor compatibility with memory card emulation. The SCPH-90006 "Patched" BIOS all ps2 bios files including the new scph90006 patched
Featured in the late-stage Slim SCPH-90000 series (released around 2008–2009). The SCPH-90006 "Patched" Context When working with PS2 BIOS files, especially if
(Hong Kong) and other 9000x series files that carry the newer v2.30 firmware. Legal & Safety Considerations When working with PS2 BIOS files
I can point you toward the right compatibility lists or setup guides.