Thanks, but that didn't work. I need a OS sollution as the key is never getting to Kodi because the system shuts down whenever this key is pressed.
It 100% does work. I have a pi3 and the same remote (amongst many others).
Just tested on a fresh install of libreelec 7.02.
Without remote.xml power button powers off.
06:14:03 1131.469360 T:1962504192 DEBUG: LIRC: Update - NEW at 50610:74 0 KEY_POWER devinput (KEY_POWER)
06:14:03 1131.469604 T:1962504192 DEBUG: OnKey: rewind (0xc4) pressed, action is ShutDown()
With remote.xml it does nothing.
06:03:28 496.663666 T:1962446848 DEBUG: LIRC: Update - NEW at 78154:74 0 KEY_POWER devinput (KEY_POWER)
06:03:28 496.663910 T:1962446848 DEBUG: OnKey: rewind (0xc4) pressed, action is noop
06:03:28 496.703552 T:1962446848 DEBUG: LIRC: Update - NEW at 78194:74 0 KEY_POWER_UP devinput (KEY_POWER_UP)
06:03:32 500.487885 T:1962446848 DEBUG: LIRC: Update - NEW at 81978:74 0 KEY_POWER devinput (KEY_POWER)
06:03:32 500.488129 T:1962446848 DEBUG: OnKey: rewind (0xc4) pressed, action is noop
06:03:32 500.528290 T:1962446848 DEBUG: LIRC: Update - NEW at 82019:74 0 KEY_POWER_UP devinput (KEY_POWER_UP)
Are you sure you've put the remote.xml in the right place (/storage/.kodi/userdata/keymaps)?
Sure you've not made remote.xml.txt?
Your ubuntu wiki info isn't relevant - the power button in libreelec is mapped in remote.xml, you can set it to do nothing (<noop>) or to do something else, just like any other button.