I just figured out a way to load Loadiine by simply pressing the WiiU browser button
Load a website with the WiiU browser + turn the WiiU off => the browser will always open this last website we visited.
Howto using self-hosting:
1. Rename loadiine's index.html on your host. Create an empty index.html file on its place.
2. Access with the WiiU browser to yoursite.com/loadiine/index.html. The empty index.html we just created will load.
3. Press the Stand by/Power off button on your WiiU.
4. Put back the original Loadiine's index.html on your host, and open your WiiU browser. Watch the magic happen!
You only need to do this once - the WiiU browser will keep this behavior. Of course, you can restore it back: simply put back an empty index.html, load the WiiU browser, close the tab or access a different site (e.g. google.com), and turn WiiU off.
I wanted to share it with you because "open loadiine twice" process becomes automatic with this!