I posted on Friday that Verizon and HTC issued an update for the HTC ThunderBolt, but after testing in a strong 4G and 3G area I confirm that it did NOT fix the may have fixed the WiFi hotspot connection failures. Thus, if you are thinking of picking up a ThunderBolt to use as a stable WiFi hotspot then I recommend you reconsider that decision. If you just want an extremely fast smartphone connection on a snappy and solid device then the ThunderBolt serves that purpose well.
I have a Windows Phone 7 and Symbian smartphones so one of the primary reasons I purchased the ThunderBolt was to have a reliable LTE hotspot to use for podcastings and working on the road. I get a very reliable 3G connection with my Nokia N8 and had high hopes for the ThunderBolt. The LTE network is blazing fast, but I kept getting kicked off the network. I have now tried two HTC ThunderBolt phones and both exhibit the same behavior, even with the latest official update installed. I am still not sure if this is a LTE network issue or an HTC ThunderBolt issue, but it seems that the ThunderBolt could not handle the network properly when used as a hotspot. Thus, I am likely going to pay the Verizon ETF and stick with my stable HSPA+ service on T-Mobile. I may try to escalate the issue with Verizon since it really is not fair that I have to pay them an ETF for service that they promised and cannot deliver on.
The HTC ThunderBolt is an awesome Android smartphone and I loved using it with HTC Sense and all of the applications. It is also incrediblly fast on LTE when used just as a smartphone, but I want more than that out of the device. It seems that Verizon has extended the free WiFi hotspot service on the Droid Charge and HTC ThunderBolt from 15 May to 15 June, as reported on the Verizon community forums by a Verizon representative. I wonder if this extension is due to the poor stability of the hotspot at this time since there is no way in the world I would ever pay for service that does not work.
UPDATE: I went to the Verizon store to see about getting a new SIM as readers suggested, but of course my ThunderBolt worked perfectly in the store. I then switched off security (I tried this before too) and have been able to maintain a WiFi connection now for a couple hours so it must have just been a network issue this morning. The WiFi hotspot definitely seems to be working better than it was before the update and I have NOT experienced any of the random restarts that I have seen others talking about. Thus, I am keeping my ThunderBolt and will put it to the test this Friday with another MoTR podcast recording and hope that my WiFi hotspot troubles are behind me.