Need help to unbrick MXQ PRO 4K

Hello

I have an MXQ pro 4k that's bricked and gets stuck on boot animation. It has allwinner h3 CPU and XR819 WiFi chip.

I can't enter recovery with av button because it just gives blackscreen and no light from led after that and I can't find firmware for it (Android 7.1.2).

Can anyone help me?

Thanks in advance