New DSTT firmware rewrites TLOZ Spirit Tracks .sav file

I downloaded the new unofficial firmware for DSTT Unofficial DSTT Kernel_v117a13_rev52a(JAP) to play Goldeneye 007 and Call of Duty Black Ops, but when I wanted to load Zelda Spirit Tracks, the .sav file was re-created and I lost all my progress!Curiously, the sav file, which always weighed 512kb, now weighs the double (1024kb)Fortunately, I always keep my .sav files in a special folder in my PC for anything that might happen. But it keeps on hapening and happening over again.Does anyone know why does this happen and how can I fix it?