If you’re looking to revert back to stock or flash a firmware image then you can boot into the LG G4 Download Mode and here is how you can do that.
Some Android devices have a download mode that gives you access to a lower level of the hardware itself. This mode is generally used by technicians but with software like the LG Flash Tool, you and I can use this mode to do things like revert back to stock, manually flash a firmware for things like downgrading, etcetera. Messing something up in Download Mode is very dangerous so please be aware that you are in a mode that has this lower level access to the software and hardware of the LG G4.
To utilize Download Mode, you’re going to need a computer with software like LG Flash Tool installed. Unless this program has been ported to Mac or Linux as well, you’re going to need a Windows PC as well. If there are ports of this software then please let me know about them in the comments section below. It is also advised that you use the USB cable that comes with your LG G4. Some users report that other USB cables do work but this is not guaranteed. If you have issues with getting into Download Mode then it might be the USB cable that you are using.
LG G4 Download Mode
- Download and Install LG’s USB Drivers
- Plug the USB Cable into the PC(not connected to the LG G4)
- Have you PC Powered On and Logged in
- Power Down the LG G4
- Press and Hold the Volume Up Button on the LG G4
- While Holding Volume Up, Plug the USB Cable into the LG G4
- Continue Holding the Volume Up Button After You See ‘Download Mode’
- Let Go of the Volume Up Button When You See the ‘Firmware Update’ Screen on the LG G4
So again, you’re going to need a PC that is on and with the original(or new) USB cable that came with your LG G4 plugged into it. At this time you shouldn’t have this USB cable plugged into the LG G4 but it should be plugged into the PC. You will most likely need LG’s USB drivers installed. You can follow the link above to download them and if they aren’t listed yet, simply download and install the USB drivers for any LG G3 model. Once that is all set up, power down the LG G4 and make sure it is completely off.
Once the LG G4 is off, press and hold the Volume Up button and while that button is held down, plug the USB cable into the bottom of the phone. This doesn’t have to be done in any amount of time. Plugging in the USB cable basically signals the LG G4 to turn on and while that is happening, if the cable is plugged in while the Volume Up button is pressed then it should boot you into the LG G4 Download Mode. If you’re watching the screen, you should see a Download Mode screen appear and if you do, continue holding the Volume Up button. After you hold this for a few more seconds then you should see it boot up into a ‘Firmware Update’ page.
This is the LG G4 Download Mode that you are looking for and it is here that you will be able to do things like manually flash a firmware image, downgrade, revert to stock, etcetera. As a word of warning, do not unplug the USB cable while anything is being flashed/installed onto your device. The same goes for pulling the battery. Now, you will need to pull the battery if you want to reboot without installing anything. However, if you unplug the USB cable or pull the battery while the PC is interacting with it(with a program like LG Flash Tool) then you could brick your device.