5G stopped after update 1.0.10

I downloaded and updated 1.0.10 while on 5G. After the update bar had run across the window, the computer lost connection to the router. I waited about 10 minutes and nothing. I unplugged, waited, and replugged in the router. 2.4G came up but not 5G. I rebooted the router on the Arris pages, still no 5G. I restarted the computer and did everything again, still no 5G. I reset the modem with a paperclip. The router default wifi name showed up. The Arris management site shows both 2.4 and 5, but no 5G showing as available on the computer, and after renaming both and resetting passwords still only the 2.4G shows up in available networks, not the 5G. 

After a 30 minute wait for tech support I was told the warranty had expired and it would cost $49.95 to get their help. Seems kind of cold after it was their update that killed the 5G on their router.

Anything else to try short of buying a new router? (from a different company!)

Update: I reset the router to factory settings. The 5G showed up long enough for me to rename and set password, connected once, then disappeared again.