[LG Optimus 4X HD] Hursty uk:
root , recorery and unlock boot loader

you must have your bootloader unlocked in order to flash kernels

( this worked for me but I can't guarantee it will work for others you can only try !! be aware when messing with firmware and bootloader you warranty could be voided )

make sure your phone is rooted you know if it is rooted because you will have superuser installed in your apps ( grey square icon with green android head on it ). if not I used this method to root my phone so try this http://xdaforums.com/showthread.php?t=2180688

if your phone is rooted next you will need a recovery this will help to backup your phone and create a restore point so in case any thing goes wrong. to install a recovery go to play store and download rom manager ( clockworkmod ) once installed open rom manger and select recovery setup. then select install or update recovery then select your phone ( lg optimus 4x hd). then select flash clockworkmod recovery. and then wait while it downloads and setup . hopefully when finished it will say succesfull. ( make sure phone is rooted or it wont work ) to check clockwork mod is working you can reboot into recovery through rom manager or power off phone then hold volume down key press power button to power up but keep holding volume down key until recovery boot up. ( be a wise option to backup phone now in recovery)

next to unlock bootloader ( so you can flash roms with kernels) go to this thread, http://xdaforums.com/showthread.php?t=2224020

and download the BL_unlock_new .rar file when its download copy it to your desktop on pc and then extract it to desktop on pc . now make sure your phone is not connected to your computer go to phone settings,then go to development options, and then select usb debugging on. once debugging is on now connect your phone to pc wait for it to connect you can keep your phone on charging mode. now open the BL_unlocking_new extracted folder on desktop on pc and double click on the BL_unlock file a box should open up on your desktop asking you to tap a key to continue so press a key now your phone should reboot and some white writing will appear on screen .on your desktop the bottom line should say please... now tap a key on computer it should say press any key to continue < waiting for device> now disconnect phone from computer look on phone screen it should say now ready! now hold power button for 10 secs and let phone reboot. to test if bootloader is unlocked on phone go to dail pad and dail this 3845#*880# you should get the hidden menu on your screen scroll down to bootloader unlock check and select then select bootloader unlock check and hopefully it should say unlock...

now you have root , recovery and bootloader unlock, now you can download a rom for this phone copy rom ( should be a zip file ) to your phone then open rom manager on phone and reboot in to recovery or power off phone, hold volume down button then press power button should now boot into recovery then you want to use volume keys to scroll down and select wipe data/factory reset with power button then scroll down and select advanced then scroll down and select wipe dalvik cache then you want to select go back then select install zip from sd card then select where you saved your rom sd card or external sd card then select rom then select install...

hopefully if that's helped you or anybody else ...