actually you can save by using a 8 mbyte (64 mbit) save data and rename it to your NDS file, then run the game if it's not working try the 32 mbyte save data (256 mbit) I tried the 256 mbit save data, it works fine, but still random crashing...
This is interesting - I tried to find some save data files online to download but have had no luck. Are they downloadable from somewhere?