Right now I bought a Nanopi Neo3, Flashed both FriendlyWrt and FriendlyCore into 16GB sd card with both Windisk32imager and Balena Etcher, and none of them worked.
Symptoms: Red light on, green light off, no IP address. Then i decided to download and flash DietPi, this time the green light started to blink but no ip address. Finally, about to surrender, i downloaded and flashed the author's Armbian image and boom, it worked like a charm. Lights blinking and Ip detected. Logged via SSH success! Thank you guys.