I found a solution that worked for me. There is a another way to upgrade to Windows 10. Go to http://windows.microsoft.com/en-us/windows-10/media-creation-tool-install
download the tool and start it, you will get 2 options, one is to upgrade and the other is to make a usb image (in other words clean install) Choose the upgrade option and the tool will start downloading and preparing the installation of Windows 10. I now have a activated Windows 10 on my chuwi. I think Microsoft only should use this way to upgrade to Windows 10 as the Windows update method seems way to buggy and many people seems to have problem with it. I really hope this will work for you.
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