[Sprint LG G3] fergie716:
Introduction

**EDIT**: Please see 4th post on how to obtain your MSL/SPC Code for the last step in restoring stock firmware

I figured it would be good to have a dedicated Factory Restore thread here for the LS990 (Sprint) G3 seeing as how we now have root and people want to be sure they can restore their phones if they screw something up.

First off, I am not presenting any new material here, I just simply gathered guides/tips/tricks from many forum members in an attempt to make it easier for LS990 users to restore their phones. Also, if you notice something wrong with the guide please say so! I have no ego here, we're all here to help one another so if I made a mistake please let me know

Hopefully this will be helpful to those who want to restore their phones back to stock and allow a thread for troubleshooting if someone is having issues

Disclaimer

I, nor anyone on XDA, is responsible for any damage done to your device. Please use at your own risk! The LG Flash Tool has the power to save your phone from a bootloop or soft-brick, however it can also do more damage if used improperly for the specified device. Please use with CAUTION.

Thank-You's/Credits

[MENTION=608699]wolfgart[/MENTION] for hosting the stock G3 files. Please thank him in his thread here

[MENTION=2078374]dokyson[/MENTION] for his guide on how to restore the LG G2. Please thank him in his thread here

[MENTION=4267589]AlanVenu[/MENTION] for pointing out Sprint users should select "Board DL" in the LG Flash Tool. Please thank him at his post here

Team Codefire for finding an exploit that allows us to root our phones. Please thank (and donate if you can) to them here

Now lets get started!

Prerequisites

Sprint LG G3 (LS990)

Windows 7/8

LG Drivers (Links will be below)

Sprint LG G3 stock .tot file (Links will be below)

Sprint DLL file for LG Flash Tool (Links will be below)

LG Flash Tool (Links will be below)

A good/reliable USB cable

Backup your data! This will format your internal storage, including user apps, SMS/MMS, Call Logs, Pictures etc. So please backup your data

Downloads

Sprint LG G3 Stock LS990ZV4 .tot file

Sprint LG G3 DLL File

LG Drivers

LG Flash Tool

Generic LG G3 DLL (**ATTENTION!!! ONLY USE IF YOU EDITED THE BUILD.PROP TO A DIFFERENT PRODUCT MODEL/BUILD ID AND ARE STUCK IN A BOOTLOOP. USE THIS DLL INSTEAD OF THE SPRINT)<------Big Thanks to engine95 and autoprime

Steps

Download all files/zips above

Double click on the LGUnitedMobile exe to install the drivers

Extract the Setup_LGFlashTool.zip and double click on the exe inside the extracted folder to install the LG Flash Tool (note: make sure you don't choose a custom directory and that it installs to C:\LG\LGFlashTool)

Inside the extracted LG Flash Tool folder (where the exe is) there is a file called "MegaLock.dll". Copy this file and paste it in the C:\LG\LGFlashTool directory (overriding the current MegaLock.dll file)

If your phone is still working (and not in a bootloop or perpetually off) plug it in to your computer and let the installation of the LG Drivers finish (if your phone is in a bootloop or it won't turn off it shouldn't be a big deal)

Unplug your phone from your computer then turn off your phone

While its turning off you can open up the LG Flash Tool program (if no desktop icon was created for the program just do a search for it within your installed apps or browse for it from the start menu). You can open it with the default setting (Korea Factory)

Once your phone is completely powered off press and hold the Volume Up button and reconnect the phone to your computer via the USB while still holding the Volume Up button until you enter Download Mode (it will look like this)

Once you're in download mode let go of the Volume Up button and wait for the drivers to install on your computer

Once the drivers have finished installing navigate to your desktop and right-click on your Computer (or This PC) icon and select "Manage" (or do a search for "Device Manager")

In the Computer Manager screen select "Device Manager" then select Ports

Look for the LGE AndroidNet USB Serial Port (COM#) (where # just means whichever port is was installed to. Ex: (COM3)). Double Click on this and select "Port Settings"

Next, select "Advanced" then change the COM Port Number to COM41. Once COM41 is selected click OK, then OK again to save your settings. Now your Device Manager should have refreshed and the LGE AndroidNet USB Serial Port should have changed to (COM41). Exit out of Device Manager/Computer Manager.

Navigate to wherever you downloaded the LGLS990_20140704_LGFLASHv160_Download.zip and extract the zip.

Back in the LG Flash Tool Program the Model Config screen should be open. Select "Manual Mode". Right below it select the LGLS990_20140704_LGFLASHv160.dll you extracted for the DLL selection (navigate to wherever you extracted it)

After that select "Add" (immediately after the DLL selection option) and select the LS990ZV4_04.51101.tot file (navigate to wherever you downloaded it)

Now, navigate to Action Mode section and select Board DL. Click OK, then click the yellow arrow in the top left corner

After you click the yellow arrow (start) button the LG Flash Tool begins examining the DLL and tot file you selected. IF everything went OK after a little wait you'll see a "READY!!" prompt under the COM41 Port.

Once you see "READY!!" sign unplug your phone from the USB, wait 5 seconds, then plug your phone back into the USB

After you reconnected your device you'll notice the flashing process begins as indicated by the progress bar. It could take a while so just hang tight and keep an eye on the progress

Sometimes the LG Flash Tool will not show 100% progress but will successfully flash the firmware so keep an eye on your phone

Once the flash is finished (either indicated by 100% progress or the PASS sign that pops up) your phone will begin to reboot into the AAT Mini OS Screen. Once at the screen hold onto the power button and select "OK", then select the "normal boot (+power)" option

After that selection is made your phone should reboot normally

Sign into everything and let your phone settle for a few minutes. Then, restart the phone

If you're missing certain apps like WiFi Calling and Sprint Bloat please follow the links provided by [MENTION=1280108]engine95[/MENTION] to restore these apps (I took apart the Sprint tot file and the apps are present, however for certain people these apps are not showing up immediately after the flash)

Success or Failure?

If your phone successfully rebooted into the system congrats! If not please look down for some trouble shooting tips (coming very soon! I need to hit the hay right now lol)

Again, I did not discover anything new, I thought it would be good to have a concise and detailed guide to restoring the LS990 to stock firmware. Hopefully this helps!