You need to hold boot key and power/reset the device to force boot from SD card, Shutdown doesn’t work properly. It reboots the board. Devices, which memory number begins with SEC710 K4B4G16, need to do.: https://forum.armbian.com/topic/7274-nanopc-t3-boot-troubles/page/3/?tab=comments#comment-83688
second serial console is enabled on a microUSB port occasional troubles with network driver https://forum.armbian.com/topic/7260-quick-review-of-nanopi-fire3/
Shutdown doesn’t work properly. It reboots the board.