This tip saved me from buying a new bananapi m3. The second bananapi that was increasingly unstable : just stopped responding. In the past only once in a few weeks, nowadays every day. So unusable. I had set it to email me every 5 minutes and it also stops doing that. Now I have set governor to performance and it's up for almost a day now. So seems good so far. If anyone has an idea why this governor change works I would certainly like to understand it. Probably some cpu-state in rest that it can't come out of? There are no signs anywhere of a crash.