Cannot write depth data to iPhone JPG "Warning: Tag 'MPImage2' is not defined"

[TeeBoek]

I am trying to edit the depth data of photos taken with an iPhone XS. Extracting works well with the command

exiftool -b -MPImage2 source.jpg > depth.jpg

but overwriting with

exiftool '-MPImage2<=depth.jpg' source.jpg does not and quits with the message

Code Select Expand

Warning: Tag 'MPImage2' is not defined
Nothing to do.

The tag is defined though. I worried that my editing somehow messed up the depth map image and tested to extract the depth map and then immediately try to embed the data I just extracted. This gave me the same error.

Just for testing I tried to write the depth image as the Thumbnail Image using exiftool '-ThumbnailImage<=depth.jpg' source.jpg which worked

Can somebody help me understanding what is going on here or experienced the same problem? Any help would be appreciated!

Photo taken with iOS 14.7.1 stock camera app
Exiftool 12.26 used on macOS 11.4 (tried zsh and bash shell)
Sample image attached

[StarGeek]

I don't believe that the MPImage tags are writable.  Check on the apporpriate Tag page to be sure.

[Phil Harvey]

Yes.  ExifTool doesn't have the ability to write MPF information.  (Also see here.)

- Phil

[TeeBoek]

Oh well than that's another dead end for me. I assumed that these MP images were just like i.e. the Google depth maps but with a different name.

I guess I will switch back to HEIF then and wait until libheif can write aux images 

Thanks!