First o all a BIG THANKS to the member Breakk from
www.movilesdualsim.com forum who found and posted this solution. The original link is this:
http://api.viglink.com/api/click?fo...oid-2-3-5%29&jsonp=vglnk_jsonp_13337954865456
In short:
1) Take a backup of your important files from the phone (contacts, applications, etc.). Propably you will not lose anything, but its better to be 100% safe. Make sure the battery is fully charged.
2) Turn off your phone and open the Device Manager on your pc. Connect the mobile to the usb port. An unknown device will appear instantly, it will disappear and then it will reappear. Right click on it and choose to update driver manualy.Depending on the OS you have (xp, vista, 7) install the appropriate driver from here
http://www.mediafire.com/?32e6q4fzx7ahoeh
You should notice now a new device that is be called "usb modem driver modify by mobileuncle.com". Make sure you have properly install the driver, disconnect and reconnect your mobile phone in the same usb port to confirm this. After successful installation the device dissappears from the Device Manager after a few seconds, don't worry - this is normal. Now unplug the phone from the usb port of your computer.
3) Download the system.img from this link
http://www.mediafire.com/?f4dahqmmucqha9c and decompress.
4) Download the flash tool and scatter.txt from here
http://www.mediafire.com/?9w5b5h1ywseljrr and decompress.
5) Open flashtool.exe and right click on the yellow foldoer button on the right that says "Scatter-loading", browse for the file MT6573_Android_scatter_Alcatel_OT_918D.txt (located in the folder you downloaded in step 4) and coose open. In the two windows that will appear about the BMT and the bootloader just press ok.
6) From the list that appeared scroll down and click in the box "Android". After that click on the word Android and browse for the file system.img (the file you downloaded in Step 3) and open it.
7) Now click the button Download in the top of the flashtool window. This will initiate a 15 second countdown at the bottom of the window, plug the 918D in the usb port during this countodown. You will see a yellow bar, wait until it goes reaches 100%. Once this is done there will be a message that will report that you successfully completed the process,also a green/white circle will appear in the flashtool and on the screen of your mobile the battery charging indicator will appear. Unplug the phone from the usb port and press the power. The phone will start and the Android logo will appear, now just wait a few minutes without touching anything on the phone (buttons or touchscreen), it will take some time to load the system.img. Once the screen displays the menu that asks for password the for 2 SIM cards you are ready, you have succesfully rooted the 918D!
Of course i have to say that I do not take any responsibility if anything goes wrong with your phone. Personally I didn't experience any problems and also didn't lose anything useful (contacts,applications or something else) from my phone. At last I have ROOT!