The RESET pin is pulled down during internal reset.
I know only the 8xx and 82xx family but IMHO the 440
is (should be) the same.
The answer IS buried somewhere in the manuals.
    Ludwig

...
>
> Howard, Marc wrote:
> > Try putting a scope/logic analyzer on your SYSRESET* line
> to see if it
> > is getting pulled down when you try to reset from U-Boot.
>
> Good point. But shouldn't the core and chip level reset still
> function,
> independent of the external reset line?  The answer might be buried
> somewhere in the PPC440 tech manuals.
>
> I might also talk to our hardware guys about this.
>
...