Android : Install CM 10.1 on non unlocked / non rooted LG optimus 4x HD

As informations are scattered on severals forum threads and various websites, I made a little summary of ressources and steps to follow to install CynogenMod 10.1 on an LG Optimus 4x HD (implies unlocking the bootloader, thus warranty lost)… it might help someone ūüėČ

Note : I did not manage to make the following to works with a (VirtualBox) Win XP Virtual machine (thought linux host) as the only usb device that can be added to the VM is “LG Modem” and the upgrade software need a direct ADB¬†connection.
There may be a solution by changing some udev rules, but as I had a windows machine in side of me, I didn’t search more than a few minutes…

Step 1 : install the unlockable V20A_00 firmware

  • Install LGUnitedMobileDriver_S4981MAN38AP22_ML_WHQL_Ver_3.8.1.exe
  • Install Fastboot driver (CT_HsPhone_General_Drivers.rar)
  • 64/DPInst.exe
  • plug phone and check that windows recognize the device (activate debug on phone)
  • unactivate Modems/LGE AndroidNet USB Modem in peripherals manager
  • boot in download mode (usual procedure: remove battery, wait 30 sec, keep vol down pushed and plug
  • usb, then put the battery back)
  • wait for device to be detected by Windows then launch KDZ_FW_UPD in administrator
  • check that “3GQCT” and “DIAG” are selected in comboboxes, select the KDZ file (V20A) then clic “Launch software update”
  • wait for the process to finish (the phone should reboot)
  • if bootloop : boot recovery (vol down + power), then factory reset and wipe cache)
  • Be aware that some firmware image are no unlockable… I got 2 the one which worked has a size of 602 Mb

Step 2 : unlock bootloader + install CWM

  • use all-in-one script (unplug usb, activate debug mode then plug usb back)
    • first question : step 2 (driver already installed in previous step)
    • option 2 : unlock bootloader (phone should reboot ask you weither¬†your are shure : if yes push vol up. When done, remove cable and battery, then put them back to reboot)
    • option 1 : root (follow on screen procedure : remove usb cable, reboot recovery, select ADB update and press any key, then reboot and check that you have a new app : su)
  • Install Rom Manager from google play and install CWM (6.0.3 minimum required for CM 10.1)¬†Note: I don’t use the option 6 of the script “all-in-one” as it installs CWM 6.0.1, not 6.0.3)
  • unplug usb cable, disable usb debuging, replug usb cable and select MTP
  • copy any p880 nightly build to external sdcard
  • boot recovery, wipe all (factory + dalvik)
  • install from zip (external sdcard) then reboot

Step 4 : additional mods / apps (personal taste)

  • Bravia_Engine_2 : install zip and modify build.prop according to the post
  • google apps (see the CM’s wiki)
  • V6Supercharger : SdCard Speed Tweaks, 3G TurboCharger, Flush-O-Matic, Fix Emissions, Wheel alignment, Detailling (clean database) on boot
  • Set density to 280 (/system/build.prop : ro.sf.lcf_density…)
  • To come : replace the kernel (I’m thinking about¬†WerewolfJB kernel)


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