After updating firmware, always do the following:
1) Hard Reset
Press the reset button on the side of the unit. Unit will reboot.
2) Reset to Factory Defaults
Got to Settings > System Setting > Reset to Factory Defaults. Unit will reboot.
3) Power Cycle (aka ‘Pull the Plug’)
Unplug the power cord from the unit. Let it sit without power for 5-10 minutes.
Plug the power back in and the unit will power up.
The above is currently mandatory following firmware changes as sometimes things don’t “bed-in” as they’re meant to. I suspect that it’s a flaw in the firmware update procedure.
You’ll need to re-enter your network password / YouTube password, etc. Let us know how you get on. ;)