How to Root the Sony Ericsson Xperia Neo V (MT11i) running Android 4.0.4 with a locked bootloader

The Sony Ericsson Xperia Neo recently got updated to Android 4.0 and while that is great news, it broke root access for many users.  This guide will show you how to fix that and regain root – read on to know how.

I.  Before You Begin

1.  This procedure works on the Xperia Neo V with a locked bootloader running Android 4.0.4.  If you have an unlocked bootloader, look to our post on the same to know how to root it.
2.  Remember to back up your data before you proceed any further!

II.  Necessary Downloads

1.  .431 Firmware (download the .431 ftf firmware for your device and save it to your computer)
2.  Flashtool v0.8.6.0.
3. .562 Kernel tft (download the .562 ftf firmware for your device and save it to your computer)
3. Root zip (download the .zip file under downloads)

III.  Flashing the .431 Firmware

1.  Double-click on flashtool .exe you downloaded above and follow the on-screen instructions to install it.
2.  Copy  both .ftf files you downloaded above to C:\Flashtool\firmwares on your harddrive.
3.  Open the Flashtool application after installation and click on the Flash icon (the one with the thunder symbol).
4.  You should be presented with two options:  Flashmode and Fastboot Mode.  Select Flashmode.
5.  Choose the kernel with the version number .431 in it and click on OK.  Follow the on-screen instructions on how to boot your device into fasboot mode and connect your device. Also, make sure”No Final Verification” is marked
6.  Reboot device.
This will have flashed your kernel back to .431 which is rootable.

IV.  Flashing the MT11i_4.1.A.0.562 Kernel

1.  Follow the same steps as described in Section III above until Step 5.
2.  On Step 5, select MT11i_4.1.A.0.562 instead of MT11i_4.1.B.0.431.
3.  Continue with the rest of the steps as in Section III.
You should now have an Xperia Neo running the .431 firmware but running a .562 kernel.

V.  Rooting the Xperia Neo V

1.  Enable USB Debugging on your device.  You can do this by heading to Settings > Applications > USB Debugging and checking the tickbox next to it.
2.  Enable installation of non-Market applications.  To do this, go to Settings > Applications and check the Unknown Sources tickbox.
3.  Connect your device to your Windows PC.
4.  Extract the DooMLoRD_v1_Xperia-2011-ICS-ROOT-emu-busybox-su.zip that you downloaded above to a folder on your desktop.
5.  From the extracted folder, double-click on runme.bat to run the DooMLoRD tool.
6.  Follow the on-screen instructions and wait for the process to be complete (your device will reboot several times during the procedure).