I have a Rock Pi 4B+ running in my living room as Pi-Hole and a print server. The power adapter I am using sometimes has some sort of power anomaly that would cause it to brownout for a moment. That alone is enough to send the rock pi hang. I have tried using the internal watchdog on the SoC, and while it does recover from a kernel panic, it seems that even the watchdog is not safe from the brownout.
So, I have an idea of using my spare Arduino board as an external watchdog; the issue is that I couldn’t find any GPIO pin that has a reset function.