I've used the internal watchdog without any issue. I mean the one you enable from systemd with RuntimeWatchdogSec=10 (where 10 iirc is a number less than 14 which is the number of seconds where the timer overflows). Not really much to configure or customize but it works reliably.
Interesting. Perhaps they fixed the driver/hardware since I last looked at this a couple years ago. At the time, no one had got it working successfully (the special device was there; it just didn't seem to do anything).
