I just got a tinker board and I tried to get it up and running. I followed the instructions from ASUS. I'm using the official Pi PSU (microusb) and a Kingston 32GB card (with an adapter to plug it into my mac). Tried booting it up and nothing happened. No HDMI output.
After a bit of reading I downloaded Armbian and used Etcher to flash the image. It came straight up with a login screen presented after a few seconds. Yay. So FWIW, TinkerOS doesn't seem to boot for me, perhaps because I just used dd to flash the image (old unix fart - I like dd) or something else.
Per Buer got a reaction from Igor in Asus Tinker won't boot