The keyword specifies for a reason. While the hardware SCPH-5500 is physically Japanese, the BIOS file contains specific NTSC-J encoding.
: Detailed technical guides and wikis provide invaluable information on the inner workings of the PlayStation, including specifics on BIOS versions, hardware revisions, and modification techniques. Playstation Scph-5500 -v3.0 Japan- Bios Scph5500.bin -Extra