Argh, I'm almost there! I thought I'd had it with the SSID
OpenWRT-KidSafe on both radio's but apparently I assumed it worked on both WiFi interfaces before I wrote here.
When I add both WiFi interfaces on the
kidsafe network (actually,
/etc/config/network), I don't get an ip address. When I enable only one WiFi interface, then I can connect to that SSID. However, on my "main" config I have the same SSID on both WiFi interfaces, so the wireless devices can figure out themselves if they connect to the 5GHz band or the 2.4 GHz band.
I'm not a specialist on this, but I guess this has got something to do with
config interface 'kidsafe' not being a bridge in