This cartridge can also be used as generic 2-4KB Atari 2600 Cartridge.
 
You can find many different ROM files on the internet by searching "Atari 2600 ROMS" or "Atari 2600 tosec"
 
You should duplicate the ROM file reaching to the size of EPROM capacity by a "HEX Editor" program. EPROM must be fully filled.