What firmware version did you upgrade from?
Does your device see the WLAN (SSID)?
Did you try deleting the wireless profile from you wireless device and recreate it?
By "Unable to connect my device" do you mean unable to get to the Internet or is you device not pulling an IP address at all?
Is the AP still accessible via GUI or SSH from your computer, can you still ping it?
The 2.4 GHz radio seems like it's broadcasting if the LED is any indication, maybe start by deleting and recreating the wireless profile on your mobile unit first.
Thank you,
Christoph S.