14 DAY TRIAL // Since Microsoft only included six smartphones on the list of supported devices for Windows 10 for Phones Technical Preview, none of which being high-end, many have been trying to find a way to push the update to non-compatible smartphones using unofficial methods.
And it looks like XDA Forums member RustyGrom found a way to upgrade his AT&T Lumia 1520 to Windows 10 for Phone Technical Preview.
Before going into details, beware that it is possible to brick your phone trying to install Windows 10 for Phones Preview on a non-compatible smartphone, and the person who came up with a solution mentions this possibility as well, so you have been warned.
First of all, you may want to know that this hack is possible by using the FiddleCore app to intercept the traffic from the Microsoft WPflights server that controls the Insider application, which is needed for installing a new version of the OS.
The Insider application allows users to edit registry info, which is why it was possible to replace the smartphone model and location. Keep in mind that smartphones made by other manufacturers like Samsung or HTC may need completely different settings in order to install Windows 10 for Phone Preview.
Anyway, here is what you'll have to do if you really want to run Windows 10 for Phones Preview on their non-supported smartphone. Once again, there's a chance that you might brick your phone, so keep that in mind before trying it out.
Full list of instructions includes installing a third-party app and a dose of luck
1. Reset your Lumia smartphone using Windows Phone recovery tool. Do not make any settings and don't even log in, instead wait until the end and do a restore after you have Windows 10.
2. Install Windows Insider application on the phone.
3. Open the application, head to about options in the app bar and take a screenshot of the settings because you will need it later. You can also write everything down for later use.
4. Download and extract WPInsidersHacks app to your computer.
5. Start the WPInsiderHacks app on PC and make sure you approve any firewall requests.
6. Then connect to the same Wi-Fi that your PC is on and edit the settings for the Wi-Fi connection to turn on the Proxy and set it to use the PC’s IP address and enter 8877 for the port.
7. Open Internet Explorer browser on the phone and head to http://[pc.ip.add.ress]:8877 where [pc.ip.add.ress] is the IP address of the PC running the WPInsidersHacks app.
8. Click on the link at the bottom to the fiddler root certificate.
9. When prompted, click open and then install to trust the certificate and then click OK at the confirmation.
10. Run the Windows Insider app and tap “Get preview builds.”
11. Tap on which custom action you would like to perform (i.e. “Set to ATT Lumia 635” and click the arrow at the bottom.
12. Accept the agreement and click the check mark at the bottom (the application should close).
13. Make sure you clear your proxy settings and run the Insider application again.
14. Once again, tap get preview builds and login with your Microsoft account.
15. Select the fast branch and click the arrow at the bottom.
16. Go into the phone settings and check for updates. If you're a lucky person, Windows 10 for Phones Preview will appear and you will be able to install. Keep in mind that in some cases you will be prompted to install Windows Phone 8.1 first and then Windows 10, so check for the updates again.
17. Lastly, go to Settings and do another reset. Then log into the phone and let it restore your previous data.
This method has been tested and worked on Lumia 1520 and Lumia 535, so it might be suitable for the rest of the non-compatible Windows 10 for Phones Preview smartphones.