Following the announcement of the Windows Phone 10 Technical Preview for a subset of devices (see my previous post http://t.co/ClVYPLlvXu, Microsoft has also published a recovery tool to let you roll back to Windows Phone 8.1 if you are not happy or experience blocking issue with this preview.
You can download the tool from http://download-fds.webapps.microsoft.com/supportFiles/phones/files/recovery/WindowsPhoneRecoveryToolInstaller.exe
In some way, we could say this is what we had with Windows Phone 7 and the Zune client to update our devices.
Then, just install the tool (use the computer you already used to link your phone with – it will be better)
The installation process is very simple, you just have to follow the wizard with no specific settings to define
Important note, this can be installed on a Windows 10 Technical Preview too 
I strongly recommend to check the option to create a shortcut on the desktop
Then you just have to launch the application (or at a later time just use the shortcut created on the desktop)
The first thing is the tool will check if there is any updates available for the tool
If your phone is not connected, you will have to connect it
If you hit the My Phone Was Not Detected it will force a device discovery
If your phone has been connected when you launched the application it will be displayed – it seems there is some sort of bugs here as the phone detected here is not my Nokia Lumia 1020
If you hit your phone, the application will gather some details about the device
And finally display the results which then will allow you to check/confirm you are running the latest available version for your device and if needed to rollback to a previous version
