[LG Optimus L90] SubliemeSiem:
#include
/*
* Your warranty is now likely void.
*
* I am not responsible for bricked devices, dead SD cards,
* spontaneous combustion, or any other host of cosmic penalties
* which may befall you, your family, or your phone.
*
*/

Over the last few months development on the LG L90 has made some great strides, up to the point where we can actually install roms! In order to do this, however, you'll need an unlocked bootloader.

The problem that arises is that there are different models of the L90, being the D405, the D405n, the D410 and the D415. For most of the models the unlock process is very similar, but for the D415 another method is needed.

This guide is aimed at explaining the entire unlock process in a complete and simple way, so even if you have no experience flashing custom recoveries or roms at all, you should still be able to follow this guide. If you run into problems, please just post a reply or send me a PM and I'll do my best to help you.

First of all I'd like to note that I did not develop any of the bin files or apks in this guide, I'm only collecting all the unlock methods in one place for easy reference. Therefore I am not responsible for you bricking your device or causing any kind of damage to it. You follow this guide AT YOUR OWN RISK! That being said, let's get to the unlocking!

What you'll need to unlock the bootloader

1. A rooted LG L90

You can root the phone by going to https://towelroot.com in your mobile browser and tapping the lambda sign. Save and install the apk (make sure unknown sources are enabled in "menu > general > security"). Google will warn you about the app, this is because of the exploit which will enable the root access. Execute the program and tap "make it ra1n", then install supersu from the play store. Open supersu and choose to rebuild the binaries. This will fail, but after a reboot supersu should be installed and working properly.

UPDATE: If towelroot doesn't work for you, you've probably got the L90 with an updated firmware. In that case you can follow this guide by [MENTION=4646325]gdjindal[/MENTION] to obtain root access. Afterwards you can follow the rest of this guide again.

2. Have adb installed.

just download the Android sdk and install it or, if you don't care about the SDK itself, the minimal adb from the bottom of this post (thanks to [MENTION=4501943]shinobisoft[/MENTION] for the upload). Now add the C:/path_to_the_sdk/sdk/platform-tools to your windows PATH variable (Windows 7: right click my computer > properties > advanced system settings > environment variables) or the foler in which adb.exe is located if you downloaded the minimal adb..

On your phone go to "menu > general > about phone > software information" and tap build version a few times untill it says you're a developer, then go to "menu > general > developer options" and enable usb debugging. Connect the phone with your PC and choose to connect in software mode and install the drivers and tools. When you get a message on your phone that your PC want to access usb debugging make sure you check the checkbox and accept. Now open a cmd prompt and type "adb devices" without the quotes. If it shows a series of letters and numbers followed by device, you're good to go. If it says unauthorized, you haven't accepted the prompt on your phone yet. If your device doesn't show up at all you haven't installed the drivers correctly.

3. Find out which device and software version you're running.

Go to menu > general > about phone > Hardware information for your Model number. Mine is LG-D405n, so my model is D405n.

Go to menu > general > about phone > Software information for your Software version. Mine is V10b-EUR-XX, so I've got version v10b.

4.1 If your model number is D405, D405n or D410, you'll need a modified aboot.bin to unlock the bootloader.

Go to the bottom of this post and download the file with your model and software version. I used the L90_D405n_v10b_hack.zip. Extract the aboot.bin in the zip file to a folder on your PC.

4.2 If your model number is D415, you'll need another method to unlock the bootloader, which is explained in this thread made by [MENTION=5913214]aSuperSaiyanG0D[/MENTION].

Unlocking the bootloader on the D405, D405n and D410

1. Open a cmd window an CD to the folder where you've saved the aboot.bin you've downloaded in step 4.1

2. Execute the following commands:

adb push aboot.bin /storage/external_SD/aboot.bin
adb shell
su
dd if=/dev/block/platform/msm_sdcc.1/by-name/aboot of=/storage/external_SD/stockaboot.bin
dd if=/storage/external_SD/aboot.bin of=/dev/block/platform/msm_sdcc.1/by-name/aboot

Right after the su command, supersu will give you a root request on your phone that you'll have to accept!

This will also make a backup of your current aboot partition as stockaboot.bin on your external SD card. If you don't have an external SD card, this won't work and you'll have to use /storage/emulated/0 (this is a zero, not the letter o) instead of /storage/external_SD/ like this:

adb push aboot.bin /storage/emulated/0/aboot.bin
adb shell
su
dd if=/dev/block/platform/msm_sdcc.1/by-name/aboot of=/storage/emulated/0/stockaboot.bin 5429599
dd if=/storage/emulated/0/aboot.bin of=/dev/block/platform/msm_sdcc.1/by-name/aboot

3. That's basicly it, you can now install a custom recovery. I suggest downloading the latest TWRP (2.8.0.0 right now) from [MENTION=5429599]shoxxy[/MENTION]'s thread, which can be found here. Just use ROM Toolbox to install it, choose rom installer, press settings > flash image and select the TWRP image from [MENTION=5429599]shoxxy[/MENTION]'s thread. Afterwards you can boot to recovery using ROM Toolbox, or by shutting down the phone, holding volume down and power untill the lg logo shows, then releasing and immediately pressing those buttons again. You should get a screen asking to perform a factory reset. Choose yes twice (don't worry, it wont actually perform the reset) and TWRP should boot up. Now you can create backups and install custom roms too!

If you're a fan of cyanogenmod, you should visit [MENTION=513620]Quarx[/MENTION]'s thread, which can be found here. His CM11 is already mostly functional (right now on some models the front camera doesn't work and the ir blaster doesn't have any software, but most other functions actually do work very well, while it is faster than LG stock and gives almost twice the battery life), so if you like CM it's a thread worth keeping an eye on.

Flashing back the stock rom (in case of a brick)

If you've bricked your device, or want to revert to stock for any reason, you can follow this guide made by [MENTION=4646325]gdjindal[/MENTION].