[LG Optimus L90] NightCrawler504:
Please read full guide before attempting anything once you have fully read and understood the process proceed with caution.

Intro:​

This is the simplified and user friendly process I used to root/ unlock-bootloader and flash recovery for my D400H. I’ve seen many guides and support for other D4xx phones but not for mine which according to original manufacturer software is a D400h model (not D400hn-be careful). Don’t know if this model is set by manufacturer for specific carrier and for branding reasons, which is my guess, but if you have a D400h phone surely this guide will help you. Personally did the research and this guide should save you quite some time, since It took me well over 8 hours to find the correct and working downloads for my D400h.

This is the simplified version so there is no need no for commands, complicated adb pushes, fastboot and other savvy tech jargon; although you will read a lot. As long as you can read follow instructions you should be golden.

As always I am I in no way responsible if you brick your phone (should not be the case but be careful make sure the files and versions of the downloads share the same specs as your d400h), rooting and unlocking your phone will void your warranty (although you can search forum on how to bring your phone back to oem state) always make backups before you start attempting anything, guide should work for other d4xx phones if you select the correct bootloader for your phone. If you are not sure what you’re doing just don’t do it, read, do your own research until you know what you are doing, or decide it’s not worth the risk.

Simplified process:

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We will:

a) Enable developer-options (enable usb-debugging, and allowing unkown sources)

-needed to be able to install KingRoot​

b) Root device

-Install KingRoot, needed to access root folders and give file browser device administrator privileges​

c) Unlock-bootloader

- needed to be able to install recovery

-Do this by swapping locked aboot file with unlocked downloaded aboot

-use your rooted file explorer es recommended​

d) Install recovery

-Flashify

- make backups and flash custom roms

-TWRP recomended​

In this specific order don’t jump the steps.

Detailed process:

A) Enable developer options:

To enable developer options you must go to your phone settings and depending on your specific android version and software you will find it in different places (still under settings menu tree) browse your menu and find Build Number once you have found it tap on top of the builder number till you receive a message that you have enabled developer options. Example of where you might find it are:

Settings > About phone > Build number

Settings > About device > Build number

Settings > About phone > Software information > Build number

Settings > About > Software information > More > Build number

Once you have seen the message enabling developer options or informing you already have them go to main settings menu and access developer options make sure to enable debugging, after that search in developer options or security menu to enable unknown sources make sure that both are enabled.

B) Root:

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This will be the easiest step. I tried many forms and the easiest is to Download KingRoot from original site, any mirroring apk site or make a google search on how to install it.

Once you have installed KingRoot go to app and follow in app instructions to root your phone, for root to work you must restart(reboot) your phone. Sometimes root doesn’t enforce so re-root using KingRoot and reboot again. Do NOT download a root checker or a SuperUser since KingRoot itself has them both built in, once it tells you your phone is rooted (built in checker) you can access king root and in the main menu is the Root Authorization option were you can add manually apps or just wait when app prompts you for authorization.

KingRoot once installed comes with a bundle, ignore purify and all the other stuff direct yourself directly to kingroot for purposes of the guide you can later decide how to proceed.

C) Unlock-bootloader

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So now that we have root privileges, download a root file browser of your preference. I would recommend Es root file explorer, once you download make sure to enable root explorer on the menu (you swipe from left to right on the main window of the es explorer to access main menu- enable root explorer).

Ok this is the part where you must pay attention and be sure on what you are doing.

To be able to install/Flash a recovery we must unlock the bootloader to do this we are going to replace the aboot on our android phone root directory for an unlocked one, we are going to do this by first downloading the correct aboot file.

To know if its the correct file first we must be sure we have a L90 D4xx phone that it’s not a Chinese copy since its processor would be different (Chinesse actualy mod hardware info so it shows the same as original in software, but we will not get into that we will assume its original) the aboot file we download is the same as for the specs of our phone. By this I mean does your phone have nfc, single or dual sim D400hn is not supported. My phone was D400h and fits description of the D405 so after unlocking my phone is now actually a D405 yeay :D

Be careful to download correct file from this link:

http://xdaforums.com/lg-l90/development/bootstack-kk-l-l90-t3118632

Once you have downloaded unlocked aboot file (unzip and extract aboot file if zipped or rar file) first copy your original aboot file that’s inside your phone and keep it somewhere accessible like your desktop or laptop. To do this you copy aboot file to phones external memory or some directory that can be accessed from your computer. THIS IS THE ONLY TIME U WILL USE A COMPUTER, though it is optional I highly recommend it. All steps of the guide are to be made from your phone directly (unless you downloaded apk mirror from your computer but again you could have made it directly from your phone).

If you brick your phone you will need original aboot file to unbrick It, via download mode and software, if you cannot do this yourself at least you can give it to the guy who is gonna fix it, having the file makes things easier. If the person who is gonna fix it cannot get a hold on the correct aboot file they wont try hard the can make more and faster money using their time in solving other simple matters they will give it back to you bricked even if its fixable just to not waste their time on it.

Aboot file is in your phone under this directory:

/dev/block/platform/msm_sdcc.1/by-name/

If you cannot get to your root directory google how to do so with your rooted explorer app.

Now that you have back up replace old aboot file with the new one or delete old file and then copy the new one in the same directory. /dev/block/platform/msm_sdcc.1/by-name/

do this with your rooted file explorer, by-name is actually a folder in there you must paste new aboot.

**DON’T reboot your phone just jet and jump directly to Recovery section

D) Install recovery

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Easy-peasy. Download Flashify from play store and use it to flash a recovery from inside the menu, this you can also Google but should be self-explanatory once you have downloaded the app and opened it jut go to Recovery Image.

Since you installed recovery before rebooting your phone and old locked bootloader is gone, because you replaced it or deleted it worse case scenario if you selected wrong aboot file you will still be able to access TWRP or CWM and replace aboot file for original there, to fix your phone if its going in boot loop.

And Voila your D400h is now a unlocked rooted D405 with recovery.

Plz share your experiences on other roms and buy and donate to the apps before mentioned since devs work hard on making and maintaining them.​