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:
I am also the owner of Junsun V1 pro 4G + 64G.
Thanks for sharing your experience with this device,
Do you also have a bluetooth problem?
I have one that I can only pair one device at a time. In addition, it happens that after pair...
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?