I have two XL4 boxes. Out of the blue our TiVo guide, TiVo Central, everything is stuck in SD mode. When I go to Settings, Displays, etc..there is no option for me to switch back to HD. Even the tech I spoke with on the phone was stumped. She suggested I hit the down thumb button, up thumb button, and play twice to make the screen go black but that didn't work either. Any suggestions? Has this happened to anyone else? Not being able to access Netflix, Amazon, etc...through the TiVo box is such a pain. Any advice is greatly appreciated!