It's 1.5K, non-contiguous (0000-03FF, 0600-07FF), with 5 unused bytes.
The Wildfire PCB connections to the microprocessor don't quite match the AMI S2150 pinout. Pin 1 is ground and 29 is +9v like the pinout shows, but +9v is also connected to pins 2 and 6- pin 2 is supposed to be D2 and pin 6 is an output. Also, pin 7 is not connected, but that should be A12, which is shown on the patent schematic. The PCB generally matches the patent schematic otherwise. I'll trace all the connections and see what's different between the chip used and the S2150 pinout.
I'll see if I can dump the chip before I decap it.