Great, I'm glad the poweroff worked!
FWIW, I think the pin is not configured as output by default on the IIx either. I needed to set the direction otherwise the IIx wouldn't power off. This might be a safety mechanism to prevent accidental bugs that might write to that address from hard powering off the machine.
In the process of figuring out the poweroff stuff, I came across some functions that looked like you could hook in to the shutdown process, so it might be possible to create an init that registers for the shutdown, and then runs the poweroff code...
FWIW, I think the pin is not configured as output by default on the IIx either. I needed to set the direction otherwise the IIx wouldn't power off. This might be a safety mechanism to prevent accidental bugs that might write to that address from hard powering off the machine.
In the process of figuring out the poweroff stuff, I came across some functions that looked like you could hook in to the shutdown process, so it might be possible to create an init that registers for the shutdown, and then runs the poweroff code...