[LG Optimus L9 P760, P765, P768, P769] donk165:
P768 Bootloader Unlock Guide + Installing Custom Recovery with fastboot + Rooting Stock ROMs via Recovery + Installing Custom ROMs via Recovery

This guide is fairly straight forward, please note; I didn't create most of these steps, I just joined them together from various other threads. This guide assumes you have experience in adb/fastboot commands and offline flashing.

Warning! - Unlocking your bootloader voids your device's warranty. You have been warned.

Make a backup of your data before following this guide!

Required Stuff

P760 V20B or V20C Europe Open KDZ and your choice of P768 V20 Jelly Bean KDZ

KDZ Offline Flashing Tools (see attachments of 1st post)

Fastboot Package (see attachment of 1st post)

ADB + Fastboot Package

CWM 6.0.3.1 Non-Touch

CWM 6.0.3.1 Touch

TWRP 2.5

SuperSU CWM Root Zip

A quick tip for opening a command prompt wherever you currently are in Windows Explorer - Shift + Right Click will add 'Open command window here'. This means you can extract fastboot and adb anywhere on your PC.

Bootloader Unlock

So far, the P768 does not have the ability to unlock the bootloader normally, so to do this, we have to flash P760 software which can unlock the bootloader. Lucky for us P768 users, flashing P760 KDZ doesnt affect our screen like P769 users. It still has problems but we are only using it to unlock - nothing more. Bootloader unlocking is a one time action - Once its unlocked, it stays unlocked if you change KDZ/ROM.

Extra step. If you need to keep all your data before doing this unlock, root with the lelus method and then install the locked bootloader version of CWM and then take a nandroid backup. You can restore it once you have custom recovery at the end of this tutorial. (Thanks to lelus for tip)

Step 1. Flash the P760 V20B/V20C Europe Open KDZ to your phone with the offline flash method. After flashing, you may need to hard reset for the phone to boot.

Step 2. Connect your phone to your PC in LG Software Mode with USB Debugging switched on.

Step 3. Connect your phone to WiFi and make sure you are able to access the internet. Then leave your phone for 30 mins. This makes sure the device is ready to be unlocked.

Step 4. Extract 'ADB_and_Recovery_Images-P768.rar'. Navigate to where 'adb.exe' is stored on your pc and open a command line (Shift + Right Click in Windows Explorer.

Step 5. Check your phone has been recognised by typing 'adb devices'. If your phone is connected, type 'adb reboot oem-unlock'

Step 6. You should have a black screen with white text with a confirmation to unlock the bootloader. Press Volume Up button to unlock the bootloader. Now you will be in LG Fastboot mode.

Step 7. Switch off the phone by holding the power button for 10 seconds. Switch your phone back on.

Step 8. Use Offline flash method to flash back to your desired P768 Jelly Bean version. After flashing, you may need to hard reset for the phone to boot.

Step 9. Once you have P768 Firmware reinstalled, boot and setup your phone.

Installing Custom Recovery with Fastboot

Now our phone doesnt allow us to switch to fastboot mode in the same way that P760 users do. I have found that using lelus's fastboot script, we can switch to fastboot and then send recovery.

Step 1. Extract fastboot.zip and install fastboot drivers by following README instructions.

Step 2. Place chosen recovery into the fastboot directory and rename it to 'recovery.img'

Step 3. After installing drivers, navigate to where 'fastboot.exe' is stored on your pc and open a command line (Shift + Right Click).

Step 4. Minimise the command line you opened, then Open 'start.bat' from extracted fastboot.zip.

Step 5. Select option 1. Switch off your phone, remove the battery and then hit enter. Insert USB cable and then insert battery after 4 seconds.

Step 6. Once you are in fastboot mode, your phone will show a black screen. Switch to the command line opened in step 2. Type 'fastboot devices' to check your device has been recognised.

Step 7. Type 'fastboot flash recovery recovery.img' to send the recovery image

Step 8. Reboot by typing ' fastboot reboot'

Extra step. If you took a backup of your data partition at the start. Restore your backup now to regain all data from pre-mod backup.

Rooting with Recovery

Now we have a working Custom Recovery, rooting is easy.

Step 1. Switch to recovery by either using 'adb reboot recovery' or by holding Volume Up + Home when switching on the phone.

Step 2. Install SuperSU by selecting 'Install ZIP from SDCARD' and then choosing 'SuperSU-v1.32.zip'

Step 3. Go to advanced and choose 'Fix Permissions', then Reboot phone.

Step 4. Install 'Busybox' from Play Store and Smart Install busybox to xbin location.

If you took a backup of your data partition at the start. Restore your backup now to regain all data from pre-mod backup.

Now your P768 is free of its shackles and should be able to run custom ROMs. If you are not interested in Custom ROMs, stop reading now....

...We have a customised version of stock ROM, and 2 CM based ROM's which are stable enough for daily use. We also have a PAC-Man ROM and MIUI V5 being developed. We also have a patch to get a few other CM based ROMs to work on our phone, SlimBean and Super Luminal work, ChameleonOS, AvatarRom and PenberRom might work.

Jishnu Sur has made a customised version of the stock ROM which includes little tweaks and extra LG features ported from other LG UI3 phone software - LG G2. Runs great and has aroma installer to select your device during install. - {Jelly Cream V1}

Artit has created a P768 version of CyanogenMod 10.1.3 and 10.2, they work really well and only have the bugs present in the p760 build - no 1080p video recording. 10.1.3 is 4.2.2 and 10.2 is 4.3 {CM10.1.3 Final} {CM10.2}

Artit has created a P768 version of PAC-Man ROM Milestone.1, I haven't tested this one yet. GPS is fixed I believe. {PAC-Man m1}

Artit has created a version of MIUI V5 for all L9's, This is my current daily driver, MIUI is a really nice feeling android experiece.{MIUI V5 Beta 2}

Artit has also created a patch to get CM based ROMs for p760 to work on our p768s. The thread with the information can be found here. Roms to patch SlimBean, SuperLuminaL, Avatar ROM, PenberRom, Chameleon OS.

Installing a custom ROM

Installing custom ROMs is as simple as wiping a couple of directories and flashing the zip file via recovery.

Step 1. Copy the custom ROM zip to your SD card and gapps if needed.

Step 2. Boot into custom recovery by switching on the device holding volume up + home + power buttons or by using a Rebooter app.

Step 3. Take nandroid backup of current ROM.

Step 4. Wipe system, data, cache and dalvik cache directories.

Step 5. Install ROM zip package + gapps if ROM requires them.

Step 6. Reboot and setup phone.

***Step 4 can be changed if you are only upgrading an existing custom ROM. For this, only wipe cache and dalvik cache and then continue the installation.

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Thanks to:

Aremcee - for the original bootloader unlock guide

cmahendra - for his offline flashing guide + bootloader unlock guide and general guidance

lelus - for his fastboot script, TeamWin Recovery for L9 and general guidance

artas182/clockworkmod team - for ClockworkMod for L9

Jishnu Sur - for his awesome Jelly Cream ROM and for developing for a phone which he doesnt own!

artit - for his work on both Jelly Cream ROM and his own custom ROMs and Patch development!

Anyone else who has helped me out during my time on the L9 Forums!