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How To Interop Unlock Nokia Lumia 710/800 & Flash A Custom ROM

In the opinion of most Windows Phone 7 users, the Nokia Lumia series represents the best breed of WP7 devices. The awesome camera, form-factor and display of the Lumia 800 and 710 have gone a long way towards endearing Nokia’s Mango phones to the masses. Given the popularity of these devices, it makes sense that the developer community has been taking an active interest in finding an interop unlock method (or in simple terms, jailbreak) for the Lumia series. Fortunately, they seem to have stricken gold (or silver, for that matter). If you are lucky, Nokia sold you your device with an unlocked bootloader, paving the way for flashing custom ROMs and attaining interop unlock. Such bootloader is not to be found in all Lumia 800s, but the owners of Lumia 710 might be a whole lot more fortunate than that. Confused? Read on, and we will try to explain matters.

Lumia Interop Unlock Custom ROM

To check if you are one of those lucky few who have got an unlocked Qualcomm boot loader, follow the steps stated below.

Instructions For Checking If Your Device Can Be Unlocked:

  1. Disconnect your Lumia 710 or Lumia 800 from your PC or charging inlet, and then turn it off.
  2. Press the Volume Up and Power buttons simultaneously while the phone is still off. A short vibration will be felt, and at this point, you have to connect your phone to the PC via a USB cable. Don’t let go of the buttons for now.
  3. Now, you will see that your system is trying to install drivers for the phone. If you don’t see it on Windows, go to the Devices and Printers menu and you will find the device driver name there.
  4. In case you are presented with the option to format the device, press No.
  5. If your Lumia 800 is being displayed as a Nokia DLOAD, you are out of luck and your phone can’t get an interop unlock for now. However, if you are lucky and the device type is USB Mass Storage, or anything to that effect, you have an unlocked boot loader!

Lumia 710 users will be able to get back their unlocked bootloader even if their device is being displayed as a Nokia DLOAD. To do so, follow these steps.

  1. Go to this link (the content is in Russian, but you should be able to find the download link near the end of the linked page), and grab the firmware provided there.
  2. Using the Nokia Care Suite, flash the firmware (downloaded in the previous step) to your 710.

Please keep in mind that you will only need to follow the above 2 steps if your Lumia 710 shows up as Nokia DLOAD in bootloader mode. Also, Lumia 800 can not be downgraded in a similar fashion, so you are stuck without an unlock for now if your Lumia 800 doesn’t show up as a USB Mass Storage device.

Disclaimer: Please follow this guide at your own risk. AddictiveTips will not be liable if your device gets damaged or bricked during the process.

All our discussion and procedures so far were just to determine whether your Lumia is capable of flashing custom ROMs or not. If, by hook or crook, you have managed to get an unlocked bootloader on your Nokia WP7, you are finally ready to flash the first ever custom ROM for Lumia 710 and Lumia 800. For now, these ROMs won’t give you a full unlock, but an interop unlock isn’t too bad, as you will be able to run most homebrew apps, and now that WP7 Root Tools (reviewed here) has been released, interop unlocked devices can do almost anything full unlocked ones can. Here is what you will have to do to flash the custom ROM to your Lumia handset.


  1. It is better if you perform this procedure on a Linux system, but it should work fine for Windows users as well. Go to this link, and grab the files for your phone (separate set of links provided for 710 and 800).
  2. For Windows, download this tool, but for Linux, you will just have to execute the following command.
    dd if=./os-new.nb of=/dev/sdX9
  3. In the above step, “X” marks the drive which has been detected by your system.
  4. Once the above step has been performed, perform a hard reset on your phone. This can be done by pressing the Power button for 10 seconds, followed by holding the Power, Volume Down and Camera button simultaneously. When your phone vibrates, let the Power button go while maintaining your grip on the other two. Now, your phone has been hard reset.

Hard resetting your device will wipe out all the data, so it is better if you create a backup beforehand. You can learn more about “dd” by heading to this post. In case you find the above instructions confusing, try your luck at the source link given below, where it is also possible to find some additional information.

[via XDA Forum Thread]


  1. This is not a detailed guide! The best thing to do would be to create a video about it on youtube or something – as opposed to just re-wording what is on numerous other websites. 

    If you have tried this actual procedure, I would appreciate it if you could inform me what to do with the 4 part files (Lumia 800-FullUnlock_Test14.part1.rar etc…). Do I flash all of them or just one? Or do I join them or something?


  2. It asks to input a activation code to get be able to sign in to windows live id after a factory reset.
    Contact microsoft and obtain the code already 😀

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