you can´t install anything to LibreELEC as LibreELEC is a read-only system.Which threads you are referring to in regard to use w_scan for a scan for tv channels? Normally this is done by the backend you use.
My backend is tvheadend, and yes its on threads about finding the correct muxes that i often find references to use w_scan.
What exactly does it mean that LibreELEC is a read-only system? Because we can still install things, like add-ons, i installed tvheadend like that. I even found a repository that had an w_scan addon (unofficial.addon.pro) but after install, in the terminal w_scan returns an error.
And isn't there a way to connect via ssh and build it? I'm just confused by your 'can't install anything' statement