On mine i/p scaler set to off, I don't use it at all. GUI still appears over HDMI. Only disapears if I set sound to Pure Direct (shuts off all video circuits).
Taken from manual:
"When in the PURE DIRECT mode, the GUI screen is not displayed
and the display on the main unit is turned off.
• If the HDMI input connector is selected, video outputs are output in
the PURE DIRECT mode.
• The channel level and surround parameters in the PURE DIRECT
mode are the same as in the DIRECT mode.
Hope this helps.