Thanks so much for this! Works great overall, no more crashes with Mame2003-plus which plaqued me before. I've got 2 questions:
1. Does online updating of the cores in Retroarch CE beta3 work? Or do I need different modified cores and upload them locally?
2. PC-engine CD games don't seem to work, through mednafen_pce_fast_libretro_ps3 and/or mednafen_supergrafx_libretro_ps3. I just get a black screen, like with SegaCD games when trying to load them without bios in the system-folder. I tried putting PC-engine bios files in the system folder, but this doesn't seem to matter. I could roll back to an older version of the core which does seem to work, but I wonder if others have this problem as well.
ps. I love the sgenpt-mix-crt.cgp shader for use with genesis and SegaCD, it looks amazing and runs like a dream!