How do I reinstall Win 10 on an official update on L640?

[Windows Central Question]

How to reinstall win 10 on an official update on L640

Today decided to roll back my 640 LTE to 8.1 in order to get a WM10 official build. I was on Redstone but wasn't quite happy with the performance. Used Windows Device Recovery Tool and everything went ok, but the question is: Which is the best way to obtain an official build? Should I use Update Advisor or Windows Insider on any of t he rings?

Thanks

 

[Thazal]

Re: How to reinstall win 10 on an official update on L640

Windows Insider is your best bet right now for a 640 I think. I recommend the Insider Release Preview ring, I like how the newest build is running on my fiance's 640. Once you've updated you can go back into Windows Insider and set it to production and you can stick with the stable builds. Also I recommend that if you want to use a backup from your previous Windows 10 install, install the release preview ring then go to "settings" > "system" > "about" > "reset your phone" at the bottom then restore your win10 backup. Restoring my fiance's Win10 backup to 8.1(new 640 because her other one broke) was a mess to deal with.