See this post Slate Plus Title Bar - #3 by michaelsage and the thread.
You can actually change the country code in etc/config/wireless.
What happens is the frequencies will change, but it will still show “US” in the top corner.
HTH.
In my view, for the ordinary user who wants to use this Travel Router and change the frequencies on the fly, GLiNET absolutely need to make this change of country much easier, preferably in the GLiNET App (and in the WebAdmin); no user should have to delve into the etc/config/wireless file to change this, so as to comply with a specific country’s frequency limitations (or benefit from that country’s wider frequency range).
k