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[Tutorial] How to flash factory images with LG Flashtool

OP bitdomo

11th April 2014, 04:19 PM   |  #1  
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Only you are the responsible if you brick your device. I tried the whole method a few times and no problems so far, but random things could happen.

What is LG Flashtool?
  • LG Flashtool is used by LG to flash firmwares to phones.

What are the advantages of using LG Flashtool?
  • The flashing process is faster than the fastboot flashing process.
  • You don't need unlocked bootloader to flash.
  • It locks bootloader and resets tamper flag.

What are the disadvantages of using LG Flashtool?
  • Your battery level must be over 10%.
  • It changes the device factory version. If your phone had KFS78N version of android initially and you flash a KRT16M firmware, then the device factory version is going to change from KFS78N to KRT16M.
  • LGD821AT-00-V10a-NXS-XX-OCT-01-2013-KFS78N-USER-16G+0 ==> LGD821AT-00-V10b-NXS-XX-OCT-31-2013-KRT16M-USER-16G+0
  • This info stored on the misc partition at the 0x00008800 offset. You can change it back to the original one if it bothers you.
  • To get your original device factory version then just open the log file in the LOG folder which is created at the location of the DLL and TOT file and search for "device factory version" text.
  • I made a flashable zip (mirror) which bacups the device factory version to /sdcard/version.txt. After the backup just copy the txt to your PC. Then here is the restore zip (mirror). Just place the version.txt to /sdcard and flash the zip to restore.

Preparation (you have to do it only for the first time)

  • Download LG drivers (mirror)and install it.
  • Download LG Flashtool (mirror)and install it.
  • Create a folder where you put the DLL and the Firmware file.
  • Download DLL: D820 (mirror) (North American version) D821 (mirror) (Global version). Place the DLL to the created folder.
  • Download firmware: D820 (mirror) (North American version) D821 (mirror) (Global version) Place the TOT file to the created folder.
  • Turn off the phone.
  • Hold down volume_up key then connect USB cable.
  • If you see these screens bellow then the phone is in Download Mode and you are on the right path:
  • Let windows to install the drivers for the new devices.
  • Change the port number to 41:
  1. Open Device Manager.
  2. Right click on LGE Mobile USB Serial Port (COMxx) (where xx is the port number).
  3. Click on Properties.
  1. Select Port Settings tab
  2. Click on Advance...
  1. Change COM Port Number to COM41

If you don't want to flash any firmware yet just hold down the power key for 10-15 secs then your phone turns on.

Flashing the firmware

  • Enter your phone to Download Mode.
  • Start LG flash tool.
  • If Model Config window does not start, then click on the sign with two cogwheels.
  1. Place a tick next at Select Manual Mode
  2. Click on "..." and select the DLL file for your device.
  3. Click on Add to add the TOT file.
  4. Click OK.
  1. Click on the yellow arrow sign to start flashing.
  1. If you see READY!!, then reconnect your phone. Then "Waiting for Connection" text will appear in the COM41 window.
  1. At 80% the phone will shut off, don't be scared.
  1. DONE! The LED on the phone is starts blinking green. Just remove the usb cable wait until the blinking stops then turn on your device.


Restore device factory version (optional)
  1. Create a new txt file called "version.txt" and open it.
  2. Paste your device factory version from the log file located in the LOG folder where the DLL and TOT file are. Search for "device factory version" text in the log file
  3. Copy version.txt to the root of the sdcard (/sdcard).
  4. Download the restore_device_factory_version.zip (mirror).
  5. Flash restore_device_factory_version.zip in recovery.

Videos

LG Flashtool:

Restore device factory version:


Credits
All the guys from [REF] [TOT] Stock Firmware Collection for Nexus 5 (D820 & D821) thread.

Last edited by bitdomo; 20th June 2014 at 09:43 AM.
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11th April 2014, 05:18 PM   |  #2  
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How is this quicker than fastboot?

Sent from my Nexus 5
11th April 2014, 05:59 PM   |  #3  
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Quote:
Originally Posted by pepdavies

How is this quicker than fastboot?

Sent from my Nexus 5

Fastboot: Phone restarts twice. Send the images to the phone memory, after the whole image has been sent, then the phone write it to the emmc from the memory.
LG flashtool: writes the images directly to the emmc.
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13th April 2014, 07:31 PM   |  #4  
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I've never really thought of Fastboot as slow by any means. Writing a system.IMG can take a few seconds, but everything else is generally done within a couple of seconds. Writing to memory sounds safer to me as well. If it ain't broke, as they say.
15th April 2014, 09:41 PM   |  #5  
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This is awesome! People its not only that it is REALLY faster and secure to flash with this, but think of it in this way, my phone got screwed up, my flash memory died there for I tried to RMA it, the fact that the bootloader was unlocked was a problem and since there was no way to fix it I had to battle for a while, I RECOMMEND THIS WAY OF FLASHING GREATLY in case something happens to your phone you can be sure your warranty will be still there!
16th April 2014, 01:04 AM   |  #6  
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does this wipe all internal storage including "internal sdcard"?
16th April 2014, 06:57 AM   |  #7  
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Quote:
Originally Posted by cnstarz

does this wipe all internal storage including "internal sdcard"?

Full system, sdcard inclosed.

This close bootloader and flash full phone (exception imei partition)
16th April 2014, 07:23 AM   |  #8  
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Quote:
Originally Posted by cnstarz

does this wipe all internal storage including "internal sdcard"?

Quote:
Originally Posted by David_Vaz

Full system, sdcard inclosed.

This close bootloader and flash full phone (exception imei partition)

and also resets tamperflag
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16th April 2014, 02:12 PM   |  #9  
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Hi, Can you help me please.I have downloaded everything and set up the drivers as instructed but when I click on start Lg flash tool to start the process I get a message saying LG USB/Parallel lock key is not detected and then a login box pops up which has the country set as Republic of Korea in the first box and then it wants an ID and password entered. SOLVED
Last edited by maxal; 16th April 2014 at 04:41 PM.
16th April 2014, 07:56 PM   |  #10  
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Great work @bitdomo on putting this together!


Quote:
Originally Posted by pepdavies

How is this quicker than fastboot?

Sent from my Nexus 5

Quote:
Originally Posted by funky_snowman

I've never really thought of Fastboot as slow by any means. Writing a system.IMG can take a few seconds, but everything else is generally done within a couple of seconds. Writing to memory sounds safer to me as well. If it ain't broke, as they say.

I think one of the main advantages that bitdomo may have forgot to mention is that this will work even if fastboot won't (in most cases). For example, say you had a bad bootloader flash, and now you cannot access the bootloader. Consequently, you are not able to flash images using fastboot. However, using LG Flash Tool (or LGNPST) should still allow you to flash your device and get back to a stock state.

Now, the one thing that remains is to figure out how to flash the device using QPST...
Last edited by efrant; 16th April 2014 at 07:59 PM.

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