Have you checked in the menu to see if there is an update facility in it? this would be the safest way, as,
loading a wrong firmware, could cause untold havoc. First I would suggest turning off the TV and also your router,
at the mains, leave it for a few minutes, then plug the router back in and leave for about 5 minutes for it to settle,
then switch the TV back on and it should pick it up.