Odroid N2+ with power button

I have built myself a little console using the Odroid N2+ and I want a better was of turning it on and off that pulling the power cable out and in.

I have a power button and have connected it to pins 9 and 11. I followed this guide but it has not worked. Is there anything I can do. Thanks

If i understand correctly, we must add a DTB file to add the instruction deleted by hardkernel ?

(Sorry, i’m a beginer in this domain …)