No Voice during calls 4.4.3 topic

Hello!
I have been having a problem where I cannot hear anyone or be heard during calls.

I am running ViperOne ROM 7.0.1 with base 4.3.3.

My question: I went to the Viper ROM website and there I found this:
" ATTENTION:

The 7.x.x rom is based on HTC latest 4.4.3 base and requires you to update your firmware.
You need to do that on your own, because we can’t install the firmare for you with the rom install.
If you don’t install the new firmware you will have*issues no voice during calls.

You can find several threads on xda how to update your firmware."

When I upgraded to 4.3.3, I didn't do anything fancy. I don't know what I did to upgrade it but I now have 4.3.3 and I never "found several threads on xda how to update my firmware."

I know this is noob, could someone send me to the thread where I can fix this, or do I have to downgrade then re- upgrade my firmware?

Thanks, sorry if this question is repeat, I did search..

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