Since i'm unlucky guinea pig for crappy sounding dvr i decided to make some more experimental stuff, but first i have to warn you.
Firmware mentioned here is made to a7la50 camera and it really can make your camera dead, not working, and impossible to recover, so
DO THIS ONLY TO YOUR A7LA30 IF YOU ARE WILLING TO BREAK IT
I did it at my own risk and i did not break anything yet, but i cannot give any guarantee that this will work for you.
I downloaded that timelapse firmware for "a7la50 no gps" model and i loaded that, camera start working with no problem, new timelapse and resolution is added to menu, and after 30 minutes test they both work just fine. Sometimes after long period hi res recording when i press stop button camera hangs and stop answering buttons, and reset button is only way to recover, if i let car power controll camera start and stop there has been no problem yet. Every video file is closed correctly even if camera hangs.
ONCE MORE, THIS MIGHT DAMAGE YOUR CAMERA PERMANENTLY
What i did?
I have first batch G90 A7LA30 dvr with crappy sound.
I downloaded this timelapse firmware packet, and inside there is FW for a7la50 no gps, i loaded that in to my camera (even if it's wrong one).
What did i get?
New higher resolution, i don't know how long time it keeps working or is it overheating in some point and destroy camera, but you can use original resolution if you like.
Timelapse, i don't know is it important, time will tell.
Sound is much better, maybe overall sound level is lower but high noises do not break sound anymore
LWDS in on menu, i did not try it, i don't care that option.
Download resolution sample images and small video at original quality
HERE
Youtube sample is here, it shows only high and low sound levels and how camera deals with them now.
Edit- updated information to above test
After serious test cycle it turns out that a7la30 can work with this firmware no more than about 10 minutes, probably due to some memory issues.
- In every video mode camera hangs in some point, or do not recycle video files.
The most important information that i got from this test is that i do want a7la70 camera because of hi resolution.