The only way I found to disable my Apollo 630 was to unplug it!
The Apollo 620 (if you don't mind an 020) has jumpers to disable the whole board or Ram so you can fit switch/s.
Not sure on the Viper, never seen one.
Also Jens has been working again on the ACA630, this sounds very interesting, I think this is a good question to ask him if its supported in his design.
Steve.
