What is the name of files?
three files actually, us_bios, EUR_bios and jpn_bios all these are BIN files
I wrote you previously, they need to be named specifically. “bios_CD_U.bin” and so on with other regions.
Is it ok to just rename them as like you mentioned
@limin Yes it is ok.
ok that being done, now the standalone emulators for sega seems not running, can you tell me any other perfectly working emulators for sega and where to put them and how, I know its a lot to ask but if you can help me it will be really great 
@limin Ok, lets start from begining 
Where you downloaded emulator?
I downloaded this one https://github.com/zfteam/picodrive-gameshell/releases
Put folder 28_picodrive into /home/cpi/apps/Menu/Emulators and bios into .picodrive and everything works.
What gameshell os you have?
Forget everything, I have road rash for PSX already downloaded but not able play, I used psx rearmed for emulator but it just quits to main menu
How do I check on what OS my gameshell is running