If you are running Windows, make sure you set it up to show file extensions.
An interesting note, almost all flashcards use the same sav files. I used to use the same 8GB between my R4i Gold, Acekard 2i, Supercards DSonei, Supercard DSTwo, DSTT, and M3 Real. All using the same saves without any problems.
It's just the ending that needs to be tweaked when it comes down to the R4i Gold since it should be using Wood R4.
Which is easy to switch, by pressing start, going into the settings and pressing R/L until you get the screen that shows sav extensions. From there just switch it from ".nds.sav" to ".sav" and your saves should work perfectly