Hi,
I had similar issues with my TB, It would very rarely get any network signal.
After Calling HTC and doing battery pull, Etc. They said to get a replacement!
Verizon wanted to try things before giving me a replacement.
First they did a battery pull, this time the 4G network came to life, maybe because of the repeater in the store?
I left and did some shopping, lost all network connectivity. Went back to Verizon, and when I got back to the store the 4G had come back. So after they called tech support and got bumped to level 2 tech,
we found out that indeed many TB's are having this issue! They changed my SIM card. 4G seemed good for the rest of that day. Next day at work, little to no signal. I again lost all network 4G,3G,1X. So I went to another Verizon store and told them the problem. Guess what they said 4G's working in the store so there is no problem. I was pretty annoyed by then, I overheard one of the Verizon coworker's telling a client to shut off 4G when you are out of area to save battery. So then I tell him to do the same and he would see I had no 3G.
But he was arguing that it's a 4G phone running an App or turning off 4G wasn't acceptable. So I asked if there was a manager because this employee was not even making sense. I asked if I was supposed to stay in the store so I would get good enough signal so I could actually get internet, some great smartphone without Data! Finally I told him to ask his co-worker to help clarify what I was saying "he had a TB" and he switched it to 3G in the store. Guess what no signal, yet the original Rep said it didn't prove anything! I said that the co-worker did the 3G switch all the time and got signal, so if mine was working properly than it would too. Finally the manager and co-worker decided to do a Factory reset, wipes all my data and Apps! But guess what after that I now had 3G in the store! So it now has been working for 2 days so far!
I did not want to wait for an update because I only have 14 day return!
hopefully this might help other find a solution, to go to 3G install an App called phone Info, then switch to CDMA Only. That was the one the Rep didn't like, so I said there is a phone access code to do the same thing ,this is just a shortcut!