DraStic

you need 2 things the gba rom and the .sav file for the gba (that is a raw cartridge save not a save state)

Under drastic/slot2
Place bothe the rom and save with the same name or they can be named slot2

So the nds rom harvestmn.nds need files named harvestmn.gba and harvestmn.sav or slot2.gba ...