I also owned MeCOOL KM9 Pro (2+16G) and tested the latest build CoreELEC-Amlogic-ng.arm-9.1-nightly_20190808.tar, using g12a_s905x2_2g.dtb (tried g12a_s905x2_2g_1gbit.dtb but ethernet doesn’t work). Result is the same as @leptdre, there is no WiFi connections listed under ‘Connections’ tag. WiFi chipset of the TV box is AP6236.