I had the same bug. And, you got ramdump mode, probably in the past, you selected from recovery the option ,,reboot to recovery,,. To fix that, you need to press the same keys , but in a different order. First flash cwm 18.104.22.168 (by thewhisp), then , remove the battery and put it back. After that, press that buttons in that order : home+power+up+down
IMPORTANT: YOU NEED TO PRESS UP+DOWN AT THE SAME TIME, AND IN 1 SECOND. (Till you see the SAMSUNG LOGO)
If now you see ,, clock work mod,, wipe data. If not repeat all steps.
It worked 100% on my s6500d, after several hours of trying.
Sent from my GT-S6500D using xda app-developers app