Since my phone prompted me to update the OS about a week ago, I've noticed that at times I'm getting no signal at all in areas where I should have excellent coverage. For example, I've always had excellent signal (4G with 4 bars) at my workplace, now randomly I have nothing at all, not even 1X. Restarting the phone seems to correct the problem in the short term, but it always comes back. It's happened at least once a day for the last week, at different times of day and in different locations (at work, at home, and on my college campus). If I'm on a wifi network I can still get texts, sometimes, but not always.