I have an i337 NC1 build Galaxy S4 (AT&T). I'm totally new to custom roming, but I wanted to give it a shot for fun. I tried using towelroot along with SuperSu, and TWRP Manager to flash TWRP onto my phone because it supposedly worked on NC1. Apparently I did something wrong because I no longer have a recovery mode. It just gives the downloading/target screen when I try to access it. Am I screwed or is there some possible way for me to fix this? Thanks!