[Windows 10 Mobile] Seyar.q:
Hello everyone,

As per the title says, I will let you know how to backup or get your Windows 10 Mobile system image. This might be helpful for those who own an unsupported phone and want to try new builds of Windows 10M.

Since at some point Microsoft will shift RS builds to Release Preview ring and currently unsupported devices can only get 10586 builds which are only available on Release Preview ring. And to get RS builds with registry trick we need to be on 10586 and sometimes due to problems we need to get back to 8.1.

So, 10586 builds are going to be replaced soon and at some critical situation we need to go back to 8.1 then we will get stuck with 8.1.

With this guide I will help you to get a copy of your Windows 10 Mobile backed up for those situation, so there won't be any need to switch back to 8.1. You can directly restore the backed up version. The backup will work as a custom ROM, so you need have your phone's bootloader unlocked to flash it.

Points to note:

-With the backup, you will be able to backup all your installed Apps and your Data (Photos, Videos...etc.).

-Backup is OS version independent, the only thing which matters is the availability of latest firmware of your phone.

Tools you need:

- Windows Device Recovery Tool

- Windows Phone Internals

- Lumia Emergency Flash Loaders (Attached one for Lumia 820, 920, 920T, 925, 1020)

For other devices you can follow this.

- Engineering SBL3s (Attached one for Lumia 520, 620, 625, 810, 820, 822, 920, 925 and 1020)

For other devices search it on Google, you may find one.

Lets start

Preparing your phone for the backup

1. First of all make sure your phone is listed in supported list of Windows Phone Internals. if yes then continue.

2. Switch back to 8.1 using Windows Device Recovery Tool.

This will download latest available firmware for your phone on the server. Once done, on your phone go to Setting > about and write the firmware version number (You may need it later.). Also don't forget to disable Store auto update to avoid Extras+Info update.

3. Before jumping to Insider Program, check for update on your phone and install all available updates (if available.)

If updates were available, probably your firmware version has also changed, because not all updates from Windows Update servers are moved to Windows Device Recovery servers.

The firmware version number is consist of 4 parts (separated by "."). If the difference between the one you installed using Windows Device Recovery Tool and the one via Windows Update is only in 2 last parts, then it won't be a big problem. Like this:

For most devices there aren't any major new firmware updates available, except those which came with Windows 10.

4. Now, you need to unlock your phones bootloader and enable Mass Storage mode. To do this you need to have Engineering SBL3 and Emergency Flash Loader for your phone. I have attached for some phones.

a). Connect your phone to PC.

b). Open Windows Phone Internals and select "Unlock bootloader" and click Ok.

This will switch your phone to Flash Mode.

c). Now, in next window you have to select .ffu image of your phone, Emergency Flash Loader and Engineering SBL3.

The .ffu image for your phone was downloaded via Windows Device Recovery Tool and the path for the downloaded one is:

C:\ProgramData\Microsoft\Packages\Products Here you can find a folder RM-xxxx (for your device). Inside the folder there is only one item with .ffu extension and you need to use that in Windows Phone Internals.

Also select proper Engineering SBL3 and Emergency Flash Loader for your device and click "Continue". Give it some time and your phone is boot loader unlocked and Mass Storage mode enabled.

A complete guide for this is also available on Windows Phone Internal - Getting started section too

5. Install Windows Insider and get the latest Release Preview (10586) update.

After getting latest Windows 10 update, I prefer to do a hard reset and continue to the backup part.

Now your phone is ready for the backup.

You have the choice whether you want to install all your Apps and then do backup (to keep your Apps backed up too) or you only want to back up the clean installed Windows 10.

Backup and Restore

1. Connect the phone to PC.

2. Open Windows Phone Internals and click on "Backup" for the left pane.

3. Select a name for your backup file

4. click "Backup phone"

The backup process will take at least an hour (depending on the amount of Apps and Data on your phone)

To restore:

Assume you are on as RS build and some problem occurs, you don't need to switch back to 8.1 to get 10586 build. You only need to restore the backup file you created above.

1. Connect the phone to PC.

2. Open Windows Phone Internal and click on "Flash" from the left pane.

3. Select the source file (the backup file you created above).

4. Click on "Flash custom ROM".

Restore process will also take an hour, be patient.

This was all.

You can use the backup file at anytime you want

Make sure that you aren't getting major firmware update from Windows Update (OTA). If you get one the bootloader will be locked back.

Correct me if anything is wrong above :).