Playstation 2 Bios Link - Internet Archive

You will likely need to search the Archive using less obvious keywords: "SCPH-30001 BIOS" (referencing a specific model number) or "PS2 romset essential files."

The only legal method:

: Files on the Internet Archive are generally safer from malware than random "abandonware" sites, but they still exist in a state of legal uncertainty. internet archive playstation 2 bios link

: You will typically find .bin files. These are often compressed into .zip or .7z archives to save space. You will likely need to search the Archive