I am running Armbian Bionic with Linux Linux 5.4.45-sunxi on an OrangePi PC Plus board. It is running HomeAssistant and a small NodeJS service. Everything is working great, however recently some random shutdowns started. I started investigating and here are my findings: I was unable to SSH or ping the device (it is connected via WIFI) so I connected to the serial pins, but that didn't work either until manual reboot. /var/log/syslog file starts with Aug 12 13:17:04 localhost kernel: [ 0.000000] Booting Linux on physical CPU 0x0 so it looks like the log from before the shutdown disappeared. last -x command only returns: ogrevanj ttyS0 Thu Aug 13 07:52 - down (00:19) runlevel (to lvl 5) 5.4.45-sunxi Wed Aug 12 13:17 - 08:12 (18:55) reboot system boot 5.4.45-sunxi Thu Jan 1 00:00 - 08:12 (18487+08:11) wtmp begins Thu Jan 1 00:00:19 1970 Checking the HomeAssistant, it looks like the program was running until 13:44 as all charts end at that time. There is no stopping or starting record in the log. There is a spike in CPU utilization chart from 30% to 88% at 13:17, then the CPU utilization returns to 30% and stays there until 13:44. The chart of free memory also spikes at 13:17 from around 800 MB to 867 MB and then returns. The CPU temperature chart shows values between 73 °C and 76 °C, so overheating shouldn't be a problem. The unattended upgrades package was removed from the system. Here is the entire /var/log/syslog: https://pastebin.pl/view/b3a82f64 What may be the cause of the shutdown? Is there some other place I can check to find out? Why is neither WIFI nor serial working? Can I add some service or something to catch the bug, next time it happens?