As in this Armbian forum I am regularly diagnosing power issues. I've answered with this info on a few different posts over the years but I wanted this in one place so my students and the Armbian forum could discuss it.   You will read over and over the importance of good power, both in the supply, the cables, and the connection. Anything that causes the voltage to drop below each boards threshold will cause problems that seem to have no explanation. The board may run and appear to be