Save file in DS Lite and DSI

Does anyone know if there is a difference with handling the save file in a Ds Lite contra a DSI ?I just updated the kids R4ids with v 1.38 and on the DS Lite The Super Mario 64 Ds. sav file is working OK -
but the same one can't run on the DSI.The game will start on the DSI if I delete the .sav file and it makes a new .sav file with the same name, but then all the progress is lost :'(

I just made a format on the SD card- and now the save file is working again...... ::)