Dudes!!! It works with last nights daily current snapshot and built kernel from repo described on top using the firmware from original linux firmware repository. Also I am using X AMDGPU driver. Rock N Roll. Let me test this a bit 🙂
Used graphics board: Sapphire Nitro+ Radeon RX 480 8G D5 OC, 1342MHz, 8GB GDDR5, DVI, 2x HDMI, 2x DP.