Hmm, it works here, using a 7i96 I connected the pins as below and input 1 will turn the machine on and off.
net power-on hm2_7i96.0.gpio.001.in halui.machine.on
net power-off hm2_7i96.0.gpio.001.in_not halui.machine.off
is it connected to P1 or TB input?
