So I have an SM-900V (Verizon Galaxy S5) and the Verizon Lollipop update came out recently. The phone receives the update via OTA and tells me I can upgrade to Lollipop, but when the phone boots off and goes into its recovery mode updating screen, the status bar doesn't move at all and for maybe 0.5 seconds it shows the little android robot and says update failed and quickly reboots the phone. Then once using the phone again, a message pops up from the OTA utility saying update failed and nothing happened to your phone. Also using Verizon's PC utility, the same error occurs. I came to android central, because I think root is the problem. So if you don't know, Verizon released this update in 2 parts. The first part is an NK7 build and is supposed to prepare the device for the actual update. My phone is currently on that build. I was rooted when updating to this NK7 build in hopes that it will unroot my device and I can easily update to Lollipop afterwards. Turns out that thats the problem. Since I updated, I did a full restore on my phone and got everything wiped, but yet when the phone boots up, there is still the little "Custom" logo that shows up. That means, from my understanding, that the phone is half rooted. I checked for root and it says I don't have it, but when going into the device files, there are still some traces of "SU" which is superuser. I came here for help because I need to know a way to either fully unroot the device, or if I'm wrong, get rid of whatever is causing the "Custom" logo. After a full restore, there are still some signs of root, and I need help. Thanks.
(EDIT): Also the error I get within settings after the update fails is 402
(EDIT): Also the error I get within settings after the update fails is 402