How to set wallpaper to default?

As title, how can I remove my current wallpaper and set it back to default?
In new leak we get error with wallpaper bar, I thought problem is wallpaper files..

You have to go into Settings, then Display, then click on the Advanced button on the bottom. Then click Reset to Carrier Wallpaper.

It's not like there are any new ones though...

Settings > Screen > Advanced > Reset

thanks