I had the same issue on the Openbox V8s, the only thing you can do is put a menu lock
and parental lock on the box.
The channels still appear but need a pin number to clear.
This is for network updating your list.
As mentioned if you delete them they come back after an update, you also have to put the two locks back on after
the update.
This wasn't really ideal as the box was for a teenagers bedroom, or get an E2 type box and you can hide all adult channels
they will scan in automatically anyway but don't appear in any of the menus.