I don’t know if anyone else are experiencing the same issue. When the avionics first boot up, there is a green “unable RNP” message on MFD. As a result, neither RNAV nor ILS vertical guidance system work. It will lock on and show green on either glide path or glide scope, but it will guide you down to the ground quite far from the runway. This is quite a dealbreaker for me. I can deal with lack of pressurization and other annoyances bur this is core functionality.