Joying Technology Co., Ltd

I have this "volume too loud + hiss" issue that lots of people are complaining about. This video shows the issue quite well:

https://www.youtube.com/watch?v=LBdwD9Jj6zM

In the YouTube description the user says Joying sent him a different harness that has amp preouts rather than the amplified signal. How can I get one too? I checked before purchasing that this would support Mazda 6 with Bose amp. Thanks!

OK I got a reply from Joying Support if anyone has this. Changing from the default CANBUS setting to:

RZC|Mazda|All|RZC(RYC)

This stops the double amp loud sound, but unfortunately the hiss is still there. I will keep investigating.