How to update WP10 insider builds on my Lumia 925?

Hi,
i have lumia 925 With build 10166 (Slow).

I tried to update it to a later build, but it shows "Phone is updated".

I have tried both resets.

Can someone help me?

The build 10166 Does not work very good.

Thanks.

Downgrade to 8.1 using the windows phone recovery tool and then update again :)