Wdtv live hdmi doesn't work any longer

it shows “Mode not supported”. And device’s warranty is out exactly one month ago! Well done WD, well done…

If your TV is saying “Mode not supported,” then HDMI *is* working;  it’s just set to a mode your TV doesn’t support.

Have you tried reseting the box back to defaults?

I would try another HDMI cable. They are not all equal. My gold plated super duper cost a fortune one (I didnt buy it, a present!) gave me problems for weeks, “it couldnt be the HDMI cable could it? as its one of the best!” I changed it for another (cheaper) and problems went away.