If you’re inclined to have the home button act in a dedicated fashion, instead of only triggering from the home screen, this is also an option as well. If you check out the following guide it gives you the information needed to customize the remotes behavior and at the end of the post you will find an example file that dedicates the home button to CEC power control that you can copy/paste into your box. This should allow you to hold down the home button from any screen to power off, and press the button once or twice to power back on picking up on the screen you left off on. The second press to power on (sometimes) is because if the device is in screensaver or sleep the first press pulls the box out of that mode only so the keymap only affects button presses after that.