Hacking Mega drive ROMS not loading

[CrazyRach82]

I'm trying to get some mega drive roms on my 2ds, using my 2016 R4 SDHC Dual Core card. I lost all my original roms so have redownloaded them.
I am using JenesisDS. Trouble is I've tried using the file ending, bin, md, smd with no success. MD, doesn't show the games at all and bin and smd lists the files but once I;ve selected them, nothing happens. I have to go back to the home screen and try again.
Does anyone know what I'm doing wrong?
Any help appreciated.

Each

 

[zfreeman]

Try renaming them to a .GEN ending. It also supports .BIN and .SMD, so they may not be in binary format. Use this to convert your ROMs: http://www.romhacking.net/utilities/383/

 

[CrazyRach82]

Thank, that worked!!