7.95.1 + Radeon RX 460 + sound 5.1 not working

Hello

I bought a few days ago 4k TV and Radeon RX 460. The first problem came with the system. There is no picture in the installation. Boot menu does not support 4k. The image was black. I had to connect the TV full hd to install Libreelec 7.95.1. After installing and connecting the TV 4K image appeared but I have a problem with the home theater. No sound on my AVR on the HDMI. Please help. On the old graphics card GeForce 610 all was well and the Radeon issue Sad

Edit.
In the menu, I selected: ALSA: HDA ATI @@@ # 0

Is this a common problem and that someone is working on it?