Updated my HTC One to the new Sense 6 OTA through AT&T. After the update I am getting zero signal at all. I have tried a wide variety of solutions; I have removed SIM card and reinserted it, I have done a factory reset to no luck, and various other tips I have read online. I am not sure how to fix this and I just need some help/advice on how to get my signal back. It reads the SIM card fine, I just don't receive signal. Thank you for your help.