Ok, agree this might not be related and just caused by the fact that one PI has no input devices connected while the other one has. Just that it was the only difference I saw.
Any other idea what could be wrong? Maybe I need to connect a input device for it to work? Also interesting that CEC is not considered a input device.
FYI the output of evtest:
Not working one:
osmc@osmc.ddorf:~$ sudo evtest
No device specified, trying to scan all of /dev/input/event*
USAGE:
Grab mode:
evtest /dev/input/eventX
Query mode: (check exit code)
evtest --query /dev/input/eventX
is one of: EV_KEY, EV_SW, EV_LED, EV_SND
can either be a numerical value, or the textual name of the
key/switch/LED/sound being queried (e.g. SW_DOCK).
Working one:
osmc@osmc.hongkong:~$ sudo evtest
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0: Wireless Air mouse Keyboard
/dev/input/event1: Wireless Air mouse Keyboard
/dev/input/event2: lircd
Select the device event number [0-2]: