Context: new Banana Pi M4 zero (rev 2) is using Wifi/BT over SDIO, which requires an sdio overlay. Thanks to Armbian team for providing it. Editing armbianEnv.txt to add "overlays=bananapi-m4-sdio-wifi-bt" did the trick for Wifi but BT is still not available (neither in standard or rolling builds)...   @c0rnelius I know you tried to figure out why, I'm missing technical knowledge to help... Digging the Internet I saw similar bluetooth issue for radxa zero 3w with aic8800, resolved usin