Sdcard LibreELEC with fixed S905X booting, no audio issue. For S905X don't delete dbt.img. Img is tested with Mini M8S and T95X and booting is successful everytime.
Tested your build with Nexbox S905x. HD audio is also working, which is a big plus for me. The only problem I still have is the scaling problem. I use 4k smpte resolution.
update: WiFi is working. Bluetooth isn't. So I can't connect my Bluetooth keyboard.
No problems with scaling if I set resolution to Full-HD 60 Hz.