For the iota issues go to your ##Data# settings see if anything is missing in there, ive noticed the that usually the username is missing. User name is your First/last
name@sprintpcs.com ex.
johndoe@sprintpcs.com
If you change that and your phone restarts and still doesnt IOTA, than you will have to sign onto sprint.com, login. Go to settings and passwords. On the bottom left it says phone acess, click on wireless web passcode and change the pw, Change it and remember it JIC. after that try connecting to the net again and it should work. If it doesnt just wait like 15 20 min.
Hope this helps you out with the 3.16 ROM issue your having.