My Roku Ultra (4670 series) functioned perfectly well until, a few days after I acquired a 4K-capable TV, the device overheating message began to display. I moved the unit to be away from all other components, and even stood it on its side to expose more surface for radiative cooling. This did not help. Then I put the Roku on top of a large ziploc bag full of ice, and the message recurred. I wish I could immerse the bloody thing in a bath of HFE, but I don't have such exotic materials on hand. I suspect the issue is one of design -- the packaging of the electronics clearly doesn't provide for the heating load imposed by standard operation while doing precisely what it's supposed to do -- stream 4K television. That's a failure of the product, and it should be rectified without cost to we who bought the thing assuming it had been designed in a way adequate for its purpose. I am contemplating stripping it of its plastic integument, and constructing a fan-cooled safety-cage to stop cats from nosing live components.
There are on the market alternatives to ROKU, and as soon as I have an income again I shall be researching them, since I haven't the least expectation that ROKU will actually do anything about this signal failure of its product.
