Many search results will lead you to ROM forums, Discord servers, or file lockers offering a free download. While technically accessible, using these downloads occupies a legal grey area at best. In the United States under the DMCA, and in most other countries under similar copyright treaties, downloading a copyrighted BIOS file you did not extract yourself is illegal.
: It typically handles games from NTSC-U, NTSC-J, and PAL regions without needing multiple files. psxonpsp660bin bios file