Sorry if this is already posted I searched everywhere... my TB, like everyones, shut down randomly before the last update. Now its been fine as long as im not in 4g. I thought everything was great until I went to LA to visit my son in the hospital. Everytime I go on 4g my phone restarts and when it doesnt restart its just screwy. GPS cant find signal, it wont hang up, it cant dial certain numbers, I heard some sim cards are problems any truth to this?