Remove the blog slug from WordPress Multisite root node

I have been looking at whether it is possible to remove blog/ from the post & category URLs on the root node in a multisite setup.

I have found the multisite sites settings and removed the blog/ part of the URL and saved. Despite it changing all of the links correctly when I click them I just end up with a 404.

If I go to the node dashboard itself and resave I get the blog/ URL rewritten into the changed multisite permalinks. Sometimes creating something like this blog/news/postname

Has anyone managed to do this in the past? I am wondering if it is possible without hacking the core or getting a bit more hands on with some .htaccess rules.

1. At blog site set Settings -> Permalinks -> Common Setting -> Default (Must select default only and don’t touch any thing, If you need to change category base, tag base set at Network Admin only)

2. At Network Admin -> Sites -> (root site) Permalink Sturcture -> /%category%/%post_id%

That it will remove /blog slug