Change HTC Vive compositor progress panel image

When HTC Vive is “paused”, like loading a new scene or pressing pause in the editor, it drops to the compositor and displays a loading screen with 3 vertical lines rotating to represent progress.

How do you change the image that displays with the progress panel? Unity logo is the default image.

SteamVR_Skybox only changes the skybox that is displayed.
SteamVR_LoadLevel LoadingScreen changes the panel image, but the progress indicator is gone.
ProgressBarEmpty and Full don’t seem to work.
And SteamVR_LoadLevel is only for loading scenes, not when you have a framerate drop, which can be tested by pressing pause in the editor.

I thought the default Unity image on the progress panel might be controlled by the Splash Image in Player Settings with the “Virtual Reality Splash Image”, but that doesn’t change it.

I know this was asked a while ago but I’ll throw this in here as I was thinking about something similar and came across this in a search.

This isn’t easy, however, I would start by asking whether an alternative thought process is required. You can create a fairly simple adaptive quality script that spots when you are not getting the frame rate you require and then adjusts using

UnityEngine.XR.XRSettings.renderViewportScale = betterScale;
QualitySettings.SetQualityLevel(betterQualityLevel, false);

I appreciate that is obtuse enough to be next to useless, but the scripts to implement that aren’t too complex, you can find my scripts here AdaptiveQuality.cs and here AdaptiveViewport.cs. Note this last script goes on your main camera in the scene.

If that still doesn’t work for you then the SteamVR_LoadLevel script is actually quite useful to pick through. As it does do what you need. Again based on some form of adaptive quality script, you can use the elements in that script to achieve what you need. The basic format is

Generate Loading Screen
Setup Loading Screen Overlay 
Load a SkyBox
SteamVR_Render.pauseRendering = true
Fade in the Loading Screen/Skybox
SteamVR_Render.pauseRendering = false
Fade out the overlays, fade in the screen you need

However, I would also be asking the question as to why the frame rate drops given that would be where I would start looking at improvements.