Sorry, second post for today, but after this Ill keep silent for a while 
I presume the current MSX core does not have OPL4 support, right? At least I cannot find anything related anywhere. The cool new MSX2+ adventure game Sales Discontinued requires OPL4 to work 
Ok, that explains it. Thanks for the infowark91 wrote: ↑Sat Oct 01, 2022 3:24 pm MSX 2/3 core is based on OneChipMSX.
For the moment OCM doesn't support OPL4 maybe someday.
http://gnogni.altervista.org/
Back on this topic:
It appears that OPL4 is "too large" for the FPGA used in OCM (12000 LEs). MiSTer on the orher hand, has 110000 LEs, so there would be plenty of space at least to my understanding.
Ther's an OPL4 design made with C here:
https://github.com/vgmrips/vgmplay/blob ... ymf278b.c
To my understanding it could be converted to VHDL/Verilog, but I could be terribly wrong (also) here.
Could someone way more sophisticated human being than me confirm this theory? 
Wasn't someone working on an advanced OPL chip for one of the arcade boards? I saw something about that mentioned in passing, but I can't remember details.
Yeah, I also seem to remember something like that but cannot now find anything anywhere. If it indeed will appear for some arcade cores that would be a great way to gain OPL4 support for other cores too