This is for OpenMSX
OpenMSX won't detect this type of cart automatically, so you need to say the cart type with:
openmsx -carta game.rom -romtype ASCII8SRAM2
OpenMSX will create a file game.rom.SRAM
to store 2KB of persistent memory (in Linux this is in $HOME/.openMSX/persistent/roms/game.rom).
Init and detect