There is a way to debrand and reinstall original, factory ROM on to the Microsoft Lumia 950 and 950XL. So if you are on 10.0.010586.36, you will go back to 10.0.010586.0. For doing this, it is important to start your Lumia 950 / 950XL in FFU download boot mode. For that, follow these steps.
Debrand Lumia 950 and 950XL
– Turn off your Lumia 950/950XL.
– Press and hold the power button to start your Lumia 950/950XL.
– It will display Microsoft logo. Now release the power button, then press and hold the volume up button. This step should be done quickly.
– Now white lightning and a white gear wheel appear on the screen of your Lumia 950/950XL. Release the volume up button and connect it to your PC.
Download Windows Phone image designer and Installation of original ROM
* We are going to use the Windows Phone Image Designer software for flashing. Download link.
* Access to the ..\LumiaFlashTools\WPID directory.
* Execute the Start.bat file.
When you start the Windows Phone Image Design app, two batch windows will also pop up – don’t’ close them. Select the Flash a Windows Phone image onto your phone option and click on the Next button. Your phone will be detected as x.MSMx.x.x.x where the different x are variables representing your Lumia 950/950XL variant. If your Lumia 950/950XL hasn’t been automatically detected by the software, you can click on the refresh button. Then click on the Change button.
* Select the FFU file
* Click on the Flash button.
* The software then proceeds at flash, in your Lumia 950/950XL, of the ROM that you previously selected.
The process will complete after few minutes. Your Lumia 950/950XL will restart automatically and you can disconnect from the PC now.