: Any NTSC-U BIOS from SCPH-39001 through SCPH-90001 works perfectly. Choose SCPH-90001 only if you dumped it yourself from that specific model; otherwise, earlier versions are equally fine.
The SCPH-90001 is a fascinating footnote in console history—the swan song of the PS2 hardware. Its BIOS represents Sony’s final, perfected lockdown of a system that refused to die. Treat it with the respect (and legal care) it deserves. ps2 bios scph 90001