I just received my Omega2+ today, and I've been experiencing this exact same problem. After initial setup, I was able to connect to my WiFi, and through that connection update the Omega2+. However, after rebooting it would not connect to my WiFi again.
I tried resetting to Factory Defaults, and got the same behaviour...connected no problem the first time, then would not connect again after rebooting.
After lathering/rinsing/repeating numerous times, trying to configure wireless via CLI instead of the console, etc., now even after doing a factory reset it won't connect at all.
A couple times I connected using a serial connection from my Mac, and tried to run wifi but kept getting a Kernel panic. After that, I had trouble getting it to reboot at all. After multiple retries, it's finally booting again, but back to the initial "connect to WiFi only once" problem.
I'm a total noob with this thing, so any help would be greatly appreciated!