Notes: We are not responsible for any negative actions that occur from the use of our tutorial, despite the unlikelihood. 

Note 2: Developer unlocking your device does not void your warranty, and is usually completely safe. You can always relock it if wanted.

Watch the above video for a basic instructional set on jailbreaking your device. This should work for most users. If not, continue down to the Advanced/Troubleshooting section.

1) Download ChevronWP7.exe from this mirror, and ChevronWP7.cer from XDA-Developers.

2) Extract the ChevronWP7.cer certificate from the ChevronWP7.zip file.

3) Attach the ChevronWP7.cer file to an email, and send the email to an account associated with your Windows Phone 7 device.

4) Open up the email on your Windows Phone 7 device, and click on the ChevronWP7.cer attachment. Once it downloads, tap it again to install.

5) Press Install when prompted to by your device to add the developer certificate.

6) Connect your phone to your PC, and make sure your device is unlocked (eg sitting on the Start screen)

7) Run ChevronWP7.exe, and check both boxes. Click Unlock, and it should succeed. At this point, your WP7 device is unofficially jailbroken. Skip down to the Prevent Windows Phone 7 from relocking section below.

Advanced/Troubleshooting

If your device does not unlock on the first try, don't worry. There are several different things you can try, listed below:

1) Make sure you're running on Windows Vista/7. For some reason, Windows XP does not appear to be supported by ChevronWP7.

2) Make sure that Zune is running, and the screen is unlocked and sitting on the start screen.

3) Try setting this registry key on your computer: [HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\WindowsPhone\\ProxyPorts]“DeviceReg”=dword:000069C5

4) Make sure your WP7 has the same date, time, and timezone as your desktop computer.

5) Try installing the Windows Phone Developer Tools

6) Locate your "hosts" file (%systemroot%\\system32\\drivers\\etc\\) and set it as Read-Only.

You can read other suggestions at XDA Developers here.

Prevent your Windows Phone 7 from relocking

After about two weeks, when connecting to Zune, your device may begin to relock itself. Microsoft is not taking counteraction here (despite the alarming message, see here). What happens is an automated check with Microsoft's servers if the device should be developer unlocked. To prevent this from happening, there's a couple different options:

1) Put your device on airplane mode when syncing. Not the most convenient method, but it will get the job done.

2) Disable Zune connection service. This will prevent your device from relocking, but will also prevent further sideloading until you re-enable it.

3) For Samsung devices: Samsung Tools, a homebrew application that keeps Samsung devices from relocking themselves and bypasses the 15 application sideload rule.

4) For all devices: Change your hosts file to block Zune from contacting Microsoft's servers. [External link]

Learn from experience? Let us know your suggestions in the comments section below. If you're wondering what to do with your newly jailbroken device, check out this page or this page.