I have a s6 stuck at logo and than go black. Recently I managed jailbreak my smg920f with successful result and I also successfully flash Nemesis custom rom using TWRP tools. For some reason I want to go back the old stock rom and using TWRP I flash back the backup. At the end TWRP warned me that it fail to restore a small portion from the backup but I continue restart the device, and it fail to boot, just appear samsung logo and go black. Anyone can help me?. By the way, sorry for bad English.