I wanted to be able to take my save file from my cartridge running lsdj and use it on gambatte on the android version of retroarch. So I backed up my .sav lsdj file using this gameboy cart tool https://play.google.com/store/apps/details?id=com.shiftfypixlz.aread.emsflasher . I renamed the lsdj.sav file to lsdj.srm and copied it over retroarch’s .srm and gambatte is acting like it has to setup a new .srm file. I thought .sav and .srm were compatible for gameboys?
Finally tested on the windows version of retroarch as well and same issue.