New hack delivers Windows Mobile 10 Technical Preview to nearly any Windows Phone 8.1 handset, no microSD required

A new hack has been discovered on XDA-Developers which will allow Windows Phone users to install Windows 10 Mobile Technical Preview on nearly any Windows Phone 8 handset.

The hack used fiddler to trick the WindowsInsider app to change the PhoneManufacturerModelName in the registry, which will subsequently lead to the app offering preview builds for other devices.  The last bit is important, as there is obviously a very high risk of bricking your handset due to this, especially if Microsoft starts delivering firmware via the Insider app.

For those brave and foolish enough to do this (DO NOT DO THIS WITH YOUR ONLY PHONE) here are the instructions in full.

1. For the Lumia 1520 (and other phones?) reset your phone using the Windows Phone recovery tool. I recommend not logging in and setting everything up yet and just waiting til the end and doing a reset and letting it restore after you’re on Windows 10. This may not be required for your device but most likely is due to the space issue cited by Microsoft. You can see your available space in the About menu of the Windows Insiders app. Before resetting mine was ~200mb and after it was ~600mb. You can try without resetting but may get an error after it tries to download and install the update.
2. Install the Windows Insider app on your phone (you will need to have a store account configured)
3. Open the insiders app and go to the about options in the app bar and screenshot/make notes/email the settings to yourself. You may need this later.
4. Download and extract the WPInsidersHacks app (found here at XDA-Developers) to your computer
5. Start the WPInsiderHacks app on pc, approve any firewall requests
6. Connect to the same WiFi that your PC is on. Edit the settings for the WiFi 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 on your phone and navigate to http://[pc.ip.add.ress]:8877 where [pc.ip.add.ress] is the IP address of the PC running the WPInsidersHacks app
8. Tap on the link at the bottom to the fiddler root certificate
9. When prompted click open and then install to trust the cert and ok at the confirmation
10. Run the Windows Insider app and tap get preview builds
11. Tap on which custom action you’d like to perform e.g. “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 app will close
13. Now clear your proxy settings and run the insider app again
14. Tap get preview builds and login with your Microsoft account
15. Select the fast branch (if you’re reading this of course you want the fast branch) and click the arrow at the bottom
16. Go into the phone settings and check for updates. With any luck you should have Windows 10 there for you to install.
17. You’ll probably want to go into the settings and do another reset and then log into the phone and let it restore your previous data

The apps and scripts can be found at XDA-Developers here and intrepid users should probably read the whole thread to see what challenges and solutions were experienced and found by others.

Once again, Microsoft has warned specifically about a risk of bricking your device (ie. render it permanently disabled) by installing unauthorised builds of Windows 10 Mobile, and those who do this do it at their own risk.  Windows 10 Mobile is still rough around the edges, and we will have a much better experience waiting for later official builds to arrive in the coming months.

Screen shot via Steve T-S, hack by RustyGrom on XDA-Developers