I have used both Cores and Photons on my home Comcast Xfinity router running on 2.4 GHz without issues. I don’t recall seeing my 5 GHz network on the Cores or the Photons.
The network is on WPA2, the router is an 802.11b/g. It is connected via ethernet to an 802.11b/g/n router that broadcasts on 5 GHz. I don’t recall seeing this network through the Photons or the Cores, but I can confirm that they are happy on the first network.
Cores were claimed on a Mac through USB. Photons, we claimed through the Android app.