I noticed that you can install a file that is not native to the Xbox One. Such as a “.wbfs” file extension. But, you can only do it via the dev portal/developer virtual drive.
I also noticed you actually CAN run .ISOs, .WBFSs, etc on Xbox One Dev Mode with a External USB, etc.
How I did that was this:
- Copy/Move an .ISO or any image to the dev file explorer.
- Refresh it.
- Copy/Move the same EXACT file/file name to the USB Drive.
- Plug it in the XB1 and run RetroArch and find that file off of the XB1 File Explorer and run it.
I did it like this, because I was testing something and I accidentally noticed it. I wonder if it has to do with “File Association Registering”?