Does not get recognized by Car Head Unit

[PatrickChenHZ]

I was able to get it recognized by Google's official Desktop Head Unit (DHU), and all negotiations went through, but it would stuck at "waiting phone" with no image displayed at all(I am testing without anbox so I modified the script to have the image test pattern feed into the video pipeline). I assumed it is an issue with DHU so I went out to try it on my two cars and they would just either never recognize AAServer at all(2022 Chevy Bolt), or recognize AAServer and it is compatible with Android Auto but never start AA negotiation(2023 Mercedes). And Server.log verify that in these cases negotiation never started, only

pre read
post read: 12
pre hSM
            
post hSM: 12
pre read
post read: 12
pre hSM

post hSM: 12
pre read
post read: 12
pre hSM
Got 51, write=2
post hSM: 12

I assumed my cars might be "too" modern and went out to buy a Walmart Radio to test it on, and got a head unit that was released 2020 with wired AA/Carplay support. And it does the same thing as my Chevy, which is it just never sees AAServer. I tried to modify the USB PID&VID to the same as my Samsung phone, assuming the head unit think AAServer is not legit. but it did nothing.

Anybody had a similar experience with it? Or any possible solution to resolve it?

Thanks,