Only to say that I successfully applied version 5.67 20181117 on Bang Good ABOX A3 android TV box (s912 + LTM8830) strictly following instructions in this thread. I also flashed internal EMMC by armbian-config. Thank you very much for all your support, and my respect to balbes150.
The boot is working well with any of meson-gxm-q200.dtb, meson-gxm-q201.dtb and meson-gxm-khadas-vim2.dtb. When I connected external USB drive, it recognized it immediately and mounted on /media folder. I added to fstab automatic mount of this drive and made bind of two folders on this disk to /tmp and /home. This increased significantly the downloading speed.
I only have problem with WiFi and Bluetooth - I cannot find how to find/install/configure appropriated drivers for LTM8830. Having WiFi is not very important, but I need BT to connect audio to the amplifier.
I appreciate any help regarding this topic.