On hidden menu, there is option to disable P2P. When Roku is reset, that setting is lost. I need to either permanently disable P2P or automatically disable it whenever Roku is powered on. Is that possible?
Short answer, no. The hidden menus are unsupported and were developed for use while testing in-house. From time to time these functions are changed or removed, and because they are unsupported you never know about it. Exactly what are you trying to disable. P2P to me means point to point, and the only thing that Roku uses that for is the WiFi direct remotes. If you turn that off you lose the remote's functionality, although depending on the model Roku you may still have IR functionality.
Dan Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.