Ok here is the solution even if your device ( k910 dual sim ) is completely bricked as was mine.
I was stuck in Lenovo logo with no success in finding right and working drivers ( windows 7 64x ) and i was not able to to get in recovery official ...everything was just - somehow - deleted...
I had locked bootloader **** and was not be able to flash cmw in working mode ****
There was nothing for me that could recover my phone even if the "hard" way with QPST or miflash etc
So....after 3 days....find this solution and hope this will help you because it is soooooooooo easy finally!
1) Download lenovo driver ( i think it is useless in fact but ok....just run it you dont have anything more to loose :P )
2a) Download and install Minimal adb
So now you have to use the right recovery image ( this file has to be inside minimal adb folder )....so here it is:
Download this ROM ( this worked for me - with other i did try i did get an error )
prefer the last updated version ( 1501 )
Put this rom in the same ADB folder and renale zip in VIBE1411.ZIP ( in order to be easier later ) :P
3) Turn off the device open Adb and write : fastboot boot recovery.img ( to have it ready )
4) Push volume + $ volume - at the same time and AFTER connect with usb to your pc - At the time the device will vibrate HIT ENTER in ADB
This will flash the recovery and after 1 minute device will open in a recovery screen with an adb update option ***
SELECT THIS adb update OPTION !
Your device kow it is ready to flash the new rom ! ( you will realize that everything is right from many usb beeps you will hear )
5)In adb console write : adb sideload VIBE1411.ZIP
This will take a little ....after that your device will reboot ! Dont panic if for a few minutes it will stuck in lenovo logo....
IT IS NORMAL AND YOU HAVE TO WAIT!
Hope this will help you.....please feel free to tell me if this worked for you.