Playstation .sbi files with PBP or even multidisc PBP

[parasven]

Does anyone have experience with Playstation game in pbp format + sbi (Subchanneldata) files? Some games need the because they are copyprotected.
Im using the core: https://github.com/libretro/beetle-psx-libretro

Using the sbi files with normal .cue/bin images does indeed work just fine.

Using the same sbi file with pbp does not work, although there seems to be code to load sbi files when using pbp files
see: https://github.com/libretro/beetle-psx-libretro/blob/6cfd34ab307d08d5bcde543a95cdcd00f54afec0/mednafen/cdrom-new/CDAccess_PBP.cpp

One line in that sourcecode even mentions multidisc pbp sbi support:

// for multi-disc images change the sbi file syntax to [filename]_[disc_number].sbi instead of [filename].sbi
if(PBP_DiscCount > 1)
{
// use a substitute char here, set the proper one in Read_TOC()
sbi_path.insert(sbi_path.length()-4, "_x");
}

Using the Syntax described in that comment did not work for me though. Or i am actually doing something wromg here.

[parasven]

The Problem was located:
When using pbp files with sbi files the extension both must be lower or uppercase.
Having them mixed will result in the emulator not finding the sbi file since linux systems are casesensitve.

multidisc PBP Systax is as described in the sourcecode comment above.

Github issue:
https://github.com/libretro/beetle-psx-libretro/issues/241