samsung smg901f problem

hi sorry im new to this don't kno if im in the rite place or not....after hours of searching the net I cant find any solutions ......what im trying to do is put my phone back to orig stock im on 5.0.2 and want to go back to the orig kitikat....and are after the orig firmwere ive looked on samfirmwere but no sucsess with my modal......smg901f.....ive tried some with odin but I got secure check fail and emmc write fail.......any help would be grait...cheers jay