I've tried everything I can think of and am unable to get the background music working for Sega CD games using Iso/Cso files with Picodrive for the PSP. Been using Picodrive 1.51 and now I've signed an Eboot for Picodrive 1.91 22.05.2017 and got that working (I'm on ofw 6.61) and still the same issue persists.
The background music plays fine when I use Bin/Cue format but that's taking up soo much space on my memory card. I've tried the bin_to_cso_mp3 converter and no luck. I tried WinISO to turn my BIN into an ISO/MP3 and no luck. I've found prepacked ISO/MP3 files and no luck. Everything that I can see is named correctly, ie SONIC CD_01 etc, the bin_to_cso_mp3 does all that for you and renamed them myself with other programmes. I've even tried converting the MP3 files into WAV and that's not worked either. I'm clearly doing something wrong, can't for the life of me think what it is though.
My PSP is a model 3003.
Any assistance would be much appreciated.