Problem also occurs on Debian Jessie. Banana Pi M1 started to freeze a few weeks ago, switiching to nighlty build 5.44 does not help. Did a complete reinstall with Debian Stretch, same Problem, froze in just under 4 hours. No log entrys, nothing Will try switching to Stretch nightlies to see if that helps.
By the way: BPi is used headless as Pi-hole and OSCam Server with USB Card-Reader attached, nothing else. Around 10% CPU-load and below 100kb/s network trafic. I do some monitoring with LibreNMS, but just before it froze, everything looked fine. No spikes on all the graphs.
Freezed on latest nigthlie after around 10 hours