I have dumped Sega Mega-CD II europe 2.11x bios.
Comes from a late UK machine (MK-4102A-50) with the smaller Sony-made pcb.
Find it here: https://drive.google.com/file/d/1HWc-XS … F2NaEuhdLt
Hopefully you will add it to your MD dat.
Cheers
https://segaretro.org/Sega_Mega-CD/Boot_ROM - this list looks complete, yours matches "1993-06-21 Sega CD 2 (Sony Model) (NA) (2.11) MK-4102A MPR-15764-T"
No, it's definitely a previously undumped EU version (MPR-15811-T). I added it to that Segaretro page on 13/08/21, I also added it to Mame. Anyway I've since realised that Redump doesn't actually have a bios dat for Sega/Mega-CD so I guess this doesn't matter 