I feel your pain. I suffer through this until I connect the HD Cable box to the AV Amp thru Magic TV MTV7000.
Meanwhile, consider connecting w/ components cables as well for watching SD channels as a workaround for now. Both output at the same time so even when the box is having HDMI handshake issues (black screen), you can still watch SD channels thru components. This way, you only need to reboot the Cable box when you need to watch HD channels.