RouterBOARD 4xx series models have hardware watchdog.
In the wiki says about watchdog as below.
This menu allows to configure system to reboot on kernel panic, when an IP address does not respond, or in case the system has locked up. Software watchdog timer is used to provide the last option, so in very rare cases (caused by hardware malfunction) it can lock up by itself. There is a hardware watchdog device available in all RouterBOARD PowerPC and Mipsbe models, which can reboot the system in any case.
RB433GL is not using PowerPC, Mipsbe. then, RB433GL does not work Hardware watchdog?
I wish to know detail about the "hardware" meaning and processing.