I did this before I found the right way (I used Total Commander to overwrite files)... And this made disappear all my music, videos even all settings and Installer history (apps haven't gone). I tryed to erase all music and videos with iTunes and then sync it back but got the same, nothing. Also tryed to Reset All Settings didn't work. btw, when syncing the sync logo appear just for a second in ipot. Help, please !