I added custom user firmware binary feature to Device Restore over USB:

In addition to the Tinker option, there are now two (sometimes three) new options:

The first has a file selector button that allows you do supply your own user firmware .bin file from your browser. This is done entirely within your browser and the binary isn’t uploaded to any servers.

The second downloads the binary from a web server. I tested it using Github Pages and it worked great.

When you use the from URL option, the URL in the browser will change to be the Custom URL restore URL. If you give that URL to someone, it will pre-populate the URL and hide the unnecessary options in the page when opened.

If your binary targets a Device OS version that there is no restore available for, then the next higher version will be used.