Hello,
The easiest way is to include the lines in the startup script window to run after every reboot of the router. This can be done through System->Custom Scripts. You must include the following lines to return to a specific profile:
tar -C / -xzf /etc/profiles/
/usr/sbin/profile.sh -u
uci set profiles.general.profile='profile'
uci commit
/sbin/luci-reload
Where profile, is the name of the profile you want to set by default.
