Freezes after about 1 week and then fails to boot any longer until reimaged

[the_bertrum]

This is indeed an odd one.  I thunk it would be useful to post the startup log here which will tell us a lot about your configuration and setup even though it won't capture the fault.

Thanks Robert, the only way I can think of getting you a startup log would be to create a new image and boot that, since you don't provide a console on the HDMI interface and therefore if I have no SSH or web access I can't access the device.  Can you suggest another way?  eg. is there a way to change the default settings and enable an HDMI console access via a local keyboard?

I was suggesting a startup log from a pre-crash image because that will tell us about your setup, but I see Tim has a better suggestion...