A custom recovery is necessary if you want to install a custom ROM or custom firmware. The stock recovery bootable partition lets us flash official firmware while the custom recovery helps us flash the unofficial build. It also comes in handy for several other features including taking a Nandroid backup. Backing up the data is important so you don’t lose any data like your phone contacts, settings, pictures and video. A Nandroid will take a current snapshot of the ROM and store it on the internal data. that way you can apply a factory reset and wipe the data.
The “Life’s Good” company launched this years flagship LG G3 smartphone under several different phone carrier networks. The following guide is for subscribers to the AT&T network only. Each network comes with a unique file. Flashing the incorrect file on your device can potentially be harmful. Look up what model number comes with the AT&T variant, then navigate your way to the Settings > About Device and check the number matches up with the guide here.
BEFORE WE BEGIN
- You must install ADB and fastboot  on your computer.
- You should have a Windows PC running anything from Windows XP and up to follow our fastboot guide.
- You can install Android SDK on Linux and Mac with different guides if you need it.
- Backup the smartphone using the built-in backup feature which lets users make copies of most of the data. You can backup the applications by navigating to the Home screen > apps > settings > scroll down the screen to where it says PERSONAL, followed by tapping the backup and reset option.
- Note that you do not need to tap the reset option because it’s not necessary to perform a hard reset on the device for the guide.
HOW TO INSTALL THE TWRP RECOVERY IMAGE ON THE LG G3 FOR AT&T
- Download the executable file for AT&T members only here .
- Use the desktop of the computer for the file. make sure it’s the same computer that has the ADB.
- Connect the LG G3 to the computer with the USB cable.
- Find the ADB folder and open the same.
- Right-click the mouse and press the Shift key on the keyboard.
- Open the command prompt window from the menu.
- Type “adb devices.”
- Now type “adb shell” and press enter.
- Type “su” and press enter.
- Type “dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/recovery” and press enter.
- Lastly, input this: “dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/recovery” and press enter.
Your device now has team Win’s custom recovery image full installed thanks to the commands. The next thing you need to do is learn how to enter the recovery mode .