Before you start, make sure you have made a complete backup of your device, also ensure you have an unlocked bootloader (this is also known as Qualcomm development bootloader). If you’re unsure, there’s an easy way to check. Simply power down your device, then press and hold volume up + power until you feel haptic feedback. Then, connect your device to your computer, and if it shows as being in disk mode (USB Mass Storage), then you have an unlocked bootloader and can proceed with the tutorial.
It is advised by the developer that the process is carried out on a Linux-based machine.
Step 1: Download DD via this link.
Step 2: Download the required custom ROM for Lumia 800 or 710, depending on which phone you have, from the official thread on XDA here.
Step 3: Make sure the device is connected to your computer.
Step 4: Next, you’ll need to locate the appropriate partition:
dd if=./os-new.nb of=/dev/sdX9(note that ‘x’ is the disk detected by your Linux distribution).
Step 5: Now, you ll need to perform a hard reset of the device. In order to do this, hold the power button for 10 seconds (which will take you out of disk mode), then press and hold power + volume down + camera until the device begins to vibrate once again. Next, release the power button while still holding volume down + camera for around five seconds or so in order to complete the hard reset.
And that’s it. you are done!
