Welcome to the Armbian Community Builds for Amlogic S9xx based TV Boxes
TV Boxes are not officially supported by the Armbian project. These builds are maintained by community members (like you).
Serial console:
Blue color line: Tool Pin TXD, orange color: Tool Pin RXD, black: Tool Pin GND
How to boot from SD card? After power on, quickly press the Function key 3 times in 2 seconds, then release the key. More at official manual.