I've ansered the question in another forum already but anyway :
You can not convert a Start to a Rider you only can use the Navcore of a Rider to make it look like one.
Since the Start is a pretty limited device it might not work all as you expect.
So before you do anything make a full backup uf your device using the Windows Explorer and not TT Home!
After that feel free to try the Rider Navcore from here :
:link: or here :
:link: