Hello. Since version 1.14.0 PicoDrive core shows version as 1.99-unknown and after launching any game just “crash” to PS2 browser. All the same on 1.15.0 and 1.16.0 versions.
I took screenshot from emulator but it’s the same on real console.
Excuse my English 
The problem is missing “retroarch-salamander.cfg” file and you need to disable “Always Reload Core on Run Content” in core settings.