I have been having the same issues since installing the update, I decided to speak to HTC this morning and it seems the only way to fix this issue is to send the phone to HTC Repair Centre. I have copied the chat session.
Having been only ever a Nokia and iPhone user in the past I thought I would try HTC and had a few issues with bluebooth disconnecting after calls in my car but other than that my migration to the HTC went well and has been running ok (with exception to the bluetooth issue) for about 2 or 3 months until this, which has blown HTC out of the water for me and looks like I won't be using one again.
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Ryan: Hi Mark, thank you for contacting HTC Support, I’m looking in to your query now. .
Mark Oldham: thank you.
Ryan: ok when did this first occur please
Ryan: and has the device been changed in any way since the issue
Mark Oldham: sometime last week after I updated it. The update is the only change and I was prompted by the phone about the update.
Ryan: ok not a problem, what have you done to try and resolve this?
Mark Oldham: am I able to roll the update back?
Ryan: you are but this requires our repair centre to flash the ROM and this is a chargeable repair process
Mark Oldham: I have carried out a factory reset which didn't seem to work and caused me more pain putting my personal settings back.
Ryan: ok would you like me to book a repair for this under the fact you cannot connect to signal?
Mark Oldham: So your update has broken my phone and you want me to pay to get it fixed?
Ryan: NO let me explain
Ryan: if you request us to flash the ROM then e it will require a fee HOWEVER if we book it in for repair under the fact that it is not connecting to a network then it should not be charged
Mark Oldham: oh ok, how long does this take and is there no plan to release an update to fix the faulty update that has affected quite a few handsets by the sounds of things?
Ryan: the repair takes 7 working days from when we receive it, unfortunately I do not have any information on future updates but can assure you this should not of happened to the device
Ryan: Please can you let me know if there is anything else that I can help you with? If I have not received a response from you, your session will timeout soon.
Mark Oldham: I'll have to go and buy another phone (not a HTC), I can't be without it for what would at least 11 days or more with the bank holiday and weekends. This is the first an last time I'll use a HTC, I'm disgusted, obviously not enough time was spent QA testing this software release, otherwise this wouldn’t have happened, were not talking about a minor bug this is basically leaves the handset not fit for purpose.
Ryan: Is there anything else I can help you with today?
Mark Oldham: Obviously not, thank you for your time.