I tried to see if it was the mini SD I was using, so I switched from my Kingston 2Gb to my Sandisk 1 Gb. Same issue, the system files got corrupted. as soon as I removed YSMenu.nds and its TTMenu files, there was no corruption. when I replaced the R4 files with the YSMenu firmware, it was perfectly fine. Has anyone else had a similar issue? I really would like to keep both of the firmware on my SD card so that I can switch as i please. I made the YSMenu files using R4Ysauto.