Question, if you boot into the u-boot console, don't boot into any O.S., but kick the watchdogs over enough to keep the system from shutting down, if you wait long enough, will the screen shut-off?

I noticed that from the /sbin/preinit shell, if you leave the N900 in it for a while 5-10 min, never timed it, the screen will shut off. Interacting with the keyboard, however, brings it back on.

I'm just wondering if that's the Maemo 5 kernel, one of the bare minimum of drivers loaded in my /sbin/preinit boot-shell (I haven't tested with the one you have in your git repo), or something lower down in the hardware having a built-in screen shut-off-when-idle feature.