So, it turns out that the SIMpad has a watchdog. This watchdog
takes a look at GPIO pin 11, which needs to be set as an output
pin and needs to be set high. If it is not, this signals that
the battery has a low voltage. And the unit powers off.

I have no idea where this is clobbered so early for the Bitsy
arch, but I just successfully booted the cerf1110 after changing
the lines:

g->gpdr = EnableRS232In | EnableRS232Out | CFReset;
g->gpsr = EnableRS232In | EnableRS232Out;

to

g->gpdr = EnableRS232In | EnableRS232Out | CFReset | (1<<11);
g->gpsr = EnableRS232In | EnableRS232Out | (1<<11);

So it now probes all the devices and turns my screen white ;).

The cerf1110 port from Inferno, I should qualify (if that
wasn't immediately obvious).

What now? I'm going to ditch most of bitsy's code and start
(mostly) fresh. 

Whoo!

--Devon