Android radio stopped working

[Kradac]

Hi, I didn't want my first post to be asking for help, but here we are...

So I got android radio for my 2002 3.0i and it was working fine for couple months, then it stopped outputting audio maybe a minute after turning on the car.

1. Turning car off and on fixed it
2. after some time I had to turn off and on 2 or more times to work.
3. last time it worked it was when I was returning home from trip and it wasn't working when I went on trip (2 hour drive in one way)
4. now only plays sound for a second

Things we did:
My friend removed headunit and connected to power supply and works just fine
Replaced AMP in headunit
Put back original radio and it works
Battery fully charged

It has business radio and HiFi amp in trunk.

Does anyone have an idea what could be issue?