You're solving the wrong problem then. Your box should not crash, it should just keep running for months without ever needing a reboot of power down.
Find out what is causing your box to crash. Most likely it is a plugin that causes it. Reflash the box without installing plugins, that's a good starting point.
Probably... ... but not restricted to plugins, custom skins and other stuff...
A bit offtopic
I'm sorry, but, OpenPli without any additional plugins installed is like.. useless to me. I like OpenPli "cleanness", gives the power to user to choose what install, but.. my opinion is that so much code 'aesthetics' makes it hard to run some outdated plugins that run without problems in other images and what Pli does not understand is that many users need the functions that those plugins offer.