I am a little disappointed the CX does not support AGA. I suppose that is a limitation of the VA2000?
Anyway, for anyone planning the do the firmware 1.4 upgrade, when I did the upgrade I was still running the 1.3 driver and the screen was distorted with mouse tracks all over the place. I was able to copy the driver into the Picasso96 drawer and rebooted, voila.
Not sure if the 1.4 driver will run the 1.3 firmware, so YMMV all around.