button does not work

[Porcinus]

There is another command you can try : 'gpio allreadall'
You may need to install Wiringpi package : 'sudo apt-get update' then 'sudo apt-get install wiringpi'

I don't remember what pin is used for B but it's 100% sure under 40.

If nothing happen when pressing B, you can try to remove and reinstall the compute module (battery removed), there is maybe just a false contact.