Ok, instead of what hlekinfr suggested above I tried something else.
By searching the forum I found another post by hlekinfr uploading his
X9310BT user backup folder (http://avic411.com/index.php?/topic/80807-moderators-please-remove-condis-hackmode-v221/?hl=%2Bsuper+%2Btestmode&do=findComment&comment=331750).
By going to http://home.comcast.net/~cinful75/x9310bt/ I used the supertestmode to boot into maintenance.
I copied all the folders/datas from my avic-f930bt on the sd-card (I finally made a backup by this).
Then i compared prg0 und prg1 at the X9310BT user backup to poin