Please note that this can and will void your warranty and while no ill effects have been suffered, I nor this forum can be held responsible with what you decide to do with your phone. Use at your own risk!
First of all, you do need to NOT be rooted. So this means you will need to use an RUU (ROM Update utility) to revert your phone back to stock.
You can get it from here:
http://tinyurl.com/22rotth
Run through the RUU. If you run into trouble with usb connection errors, or other troubles, you can try these suggestions:
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Having troubles with the RUU giving connection errors? Do this.
Go to start, and in the search/run box, type
%temp%
Delete all that you can. Make sure the RUU is not running in the background.
Now run the RUU again. Once it starts to the first screen, it has extracted the files to the temp directory. You can then copy them to a safe place. It will be a long winded numbered folder, with a similar subfolder.
Once you have copied it to a safe place, you can then copy adb.exe, fastboot.exe, and adbwinapi.dll from the latest SDK into it, overwriting the older copies. Then start the RUU by executing ARUWizard.exe. This fixed the problem for me.
Otherwise, you can also use the extracted files to create an image that HBOOT can load. Search for rom.zip in those files and rename it to PB31IMG.zip and put it on your sdcard. Turn off your phone and then hold DOWN volume and power to get into the HBOOT screen. Let it scan through the files and when it asks to run update, say yes and let it do its thing. It will reboot at least once during update.
Once you are back to stock, you can now provide the leaked update.
MD5 hash is 68518f450fd4b15c696441f5f93deff4.
Link can be found here:
dinc_ota.zip
or
dinc_ota.zip - 4shared.com - online file sharing and storage - download
Copy this zip file to your sdcard, renaming it to update.zip.
Now power down your phone.
Hold DOWN volume and power to get to HBOOT. It will do its scanning thing. If you still have the RUU on there, say NO to updating and NO to rebooting. Once you get to the menu with fastboot, recovery, etc