There appears to be several classes of reboots as per this bug report

https://bugs.maemo.org/show_bug.cgi?id=6334

One related to wakeup or screen blanking. Nokia engineer comment below to try and track this one down

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Here's one more thing that the people suffering from frequent "wakeup from
idle" 32wd_to reboots could try out:
- increase the screen blank timeout to the maximum (2 minutes)
in the control panel display applet
- instead of letting the screen blank on its own, use the screen
lock key on the right side to blank & unblank the screen

Does that significantly reduce the frequency of reboots?
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