In the Genie software if you go to ADVANCED tab > Advanced Setup > Wireless Settings are there 2 seperate places to Enable Wireless Router Radio for 2.4G and 5G? If so, uncheck the 5G.
Also for Mode. Up to 130 Mbps is the default and allows 802.11n and 802.11g wireless devices to join
the network. g & b supports up to 54 Mbps. The 300 Mbps setting allows 802.11n devices to
connect at this speed.