RetroPie PCSX (PSX) Japanese BIOS

[backstander]

I have RetroPie setup to play the US version of PlayStation games but I can't get the Japanese games to work.

I have these PSX BIOS files in my BIOS directory right now (1st one uppercase & the rest lowercase):
SCPH1001.BIN
scph5500.bin
scph5501.bin
scph5502.bin

From my knowledge PSX BIOS files ending with 00 are Japan, 01 are US and 02 are Europe. So I've also tried both SCPH1000.BIN and SCPH7000.BIN in uppercase and lowercase but it doesn't seem to work. Am I missing something here?

[ProxyCell]

Hi @backstander do any of your BIOS files have a CRC32 checksum of f2af798b ?
https://github.com/RetroPie/RetroPie-Setup/wiki/Playstation-1

[backstander]

I have one named SCPH100.BIN with the CRC32 checksum of f2af798b
I believe this is for the Japanese version of the PSOne but I haven't got this one to work either with all uppercase or all lowercase. Is the name incorrect?

[Douggernaut]

Here's a list of suggested checksums for a lot of BIOS files: https://github.com/libretro/libretro-super/blob/master/dist/info/pcsx_rearmed_interpreter_libretro.info

[backstander]

My version of scph5500.bin has the correct MD5 checksum of 8dd7d5296a650fac7319bce665a6a53c and the CRC32 checksom of ff3eeb8c

I think it might be a filename issue. I'll experiment with added a dash in it like scph-5500.bin

Edit:
I've tried many filename cases but non seam to work when trying to play Japanese games but I did find out that it really doesn't matter what case the BIOS files are to play the US games and also worked with just about every BIOS version (US games playing with any J, E and U BIOS files 10x, 100x, 300x, 350x, 500x, 550x, 700x and 750x). Some US games will even play without a BIOS file but it gives a quick message stating "no BIOS found, expect bugs!"

I'm testing with 2 Japanese games: Captian Commando and Nekketsu Oyako. Maybe neither one of these work with the emulator.

Does anyone out there have any Japanese games working and which one(s) did you get working?