Regarding internal microphone I wasn't happy with them. Fortunately my units came with cable for external mic. I bought additional mic and installed it, now voice is much better.
Screens of my unit you can find here:
let me know if you want more info
I also uploaded mentioned firmware:
Can you please post a Screenshot from your complete systeminfo here, maybe I have an update / or the same version to downgrade it if the new fw will not fit.
Thanks for helping, please find attached screenshots,
nobady can answer?