[GUIDE]Install custom Roms with locked bootloader.

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EdwinMoq

Recognized Developer
Dec 30, 2014
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I found a way to install a custom Rom with locked bootloader. I tried on my P769 and it worked. Hope this can help.

As many of you know, the phone bootloader uses a signature check of boot and recovery images, so if you install a custom Rom on a phone with locked bootloader it will give you a Security Error.

Users of the LG G3 were able install custom images by signing them before installing, so it wont give you a security error. It seems the LG G3 uses the same signature keys than the L9, because i tested it an worked. The phone has to be rooted for this to work.

Method 1: Batch script.

1. Download the attached bump.zip file and extract it.

2. Rename the zip file of your custom to rom.zip and the recovery image to recovery.img and copy both files to the bump folder.

3. Run the Bump batch script (bump.cmd). It will sign the images.

4. Use Flashify to flash the bumped recovery. Reboot and flash the bumped ROM.

This script will automatically unpack the rom zip file, sign the boot and recovery images and then repack the rom zip, so You don't need to do it manually.


Method 2: Manual.

1. Dowload the Windows version of Bump from here: http://xdaforums.com/lg-g3/general/bump-window-version-t2956829

2. Download a custom recovery for your phone. (For the P769 i used this: http://www.mediafire.com/download/o0f73qm508hd0p3/BobZ_p769_4.4.2_recovery.img. Download the custom Rom you wish to install and install Flashify from the Play Store.

3. Extract the Bump zip file to any folder. Copy the your recovery image to the same folder.

4. Open your custom Rom zip file with Winrar or any other archive manager. In the root of the zip file there's a file boot.img. Extract it to the Bump folder. After extracting it, in the Winrar window right click on the boot.img file and select 'delete files' to remove it from the zip. After You're done close Winrar.

Capture2.png


Capture3.png


5. Go to the Bump folder and drag the boot.img file to the Bump.exe program and do the same with the recovery image. It will create a "Bumped" (Signed) version of the images. delete the original boot image file and rename to the Signed version from 'boot_bumped.img' to 'boot.img'. Open the rom zip file and drag the new boot.img file to the Winrar window to add it to the flashable zip. Then copy the Signed recovery image and the Rom zip file to the phone memory card.

Capture.png


Capture6.png


6. In the phone open Flashify and tap on Recovery Image. Then tap on 'Chose a file' and go to you memory card and select your signed Recovery image. After flash is complete you can tap on reboot and the phone will start in recovery mode. Since the image is signed there will not be any security errors.

Screenshot_2015_11_15_23_07_35.png


Screenshot_2015_11_15_23_07_51.png


Screenshot_2015_11_15_23_09_01.png


7. Now you can wipe data and flash your rom.

Always make a CWM backup before performing those steps. And make sure you Sing (Bump) any image before flashing. If you don't it'll end on a security error. I'm not responsible of any data loss. I tested it with CWM, TWRP. Also CM11 and CarbonRom for P769 work fine.

The credits of this goes to the developers of the Bump program. I'm just sharing how i did it on my LG L9 for those interested.
 

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EdwinMoq

Recognized Developer
Dec 30, 2014
535
706
Santo Domingo
Is that possible? The bump program I used is a windows application, so it can't be ran in Android. There's also a python script but I'm not aware of a python version for android and I haven't tested it. I was thinking of a batch scrip that can be used on the computer. It's easier that way.
 
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Shoqovi

Member
Nov 24, 2011
32
2
Belgrade
can I try this method on L9 768, 20c rom....?
i tryed to unlock bootloader few times but no luck :/
So it cant be bricked with this method?
thanks
 
E

EdwinMoq

Recognized Developer
Dec 30, 2014
535
706
Santo Domingo
Shoqovi said:
can I try this method on L9 768, 20c rom....?
i tryed to unlock bootloader few times but no luck :/
So it cant be bricked with this method?
thanks
Click to expand...
Click to collapse
This method should work with many LG phones. As long you sign the recovery and boot images before flashing you'll be fine. Just make sure tu use the correct one for your phone.

For the P768 you can find the recovies here: http://xdaforums.com/showthread.php?t=2733471

Extract the recovery.img file from the flashable zip with winrar and sign it and it should work. Don't forget to sign the boot.img of the rom before flashing.
 
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    EdwinMoq
    I found a way to install a custom Rom with locked bootloader. I tried on my P769 and it worked. Hope this can help.

    As many of you know, the phone bootloader uses a signature check of boot and recovery images, so if you install a custom Rom on a phone with locked bootloader it will give you a Security Error.

    Users of the LG G3 were able install custom images by signing them before installing, so it wont give you a security error. It seems the LG G3 uses the same signature keys than the L9, because i tested it an worked. The phone has to be rooted for this to work.

    Method 1: Batch script.

    1. Download the attached bump.zip file and extract it.

    2. Rename the zip file of your custom to rom.zip and the recovery image to recovery.img and copy both files to the bump folder.

    3. Run the Bump batch script (bump.cmd). It will sign the images.

    4. Use Flashify to flash the bumped recovery. Reboot and flash the bumped ROM.

    This script will automatically unpack the rom zip file, sign the boot and recovery images and then repack the rom zip, so You don't need to do it manually.


    Method 2: Manual.

    1. Dowload the Windows version of Bump from here: http://xdaforums.com/lg-g3/general/bump-window-version-t2956829

    2. Download a custom recovery for your phone. (For the P769 i used this: http://www.mediafire.com/download/o0f73qm508hd0p3/BobZ_p769_4.4.2_recovery.img. Download the custom Rom you wish to install and install Flashify from the Play Store.

    3. Extract the Bump zip file to any folder. Copy the your recovery image to the same folder.

    4. Open your custom Rom zip file with Winrar or any other archive manager. In the root of the zip file there's a file boot.img. Extract it to the Bump folder. After extracting it, in the Winrar window right click on the boot.img file and select 'delete files' to remove it from the zip. After You're done close Winrar.

    Capture2.png


    Capture3.png


    5. Go to the Bump folder and drag the boot.img file to the Bump.exe program and do the same with the recovery image. It will create a "Bumped" (Signed) version of the images. delete the original boot image file and rename to the Signed version from 'boot_bumped.img' to 'boot.img'. Open the rom zip file and drag the new boot.img file to the Winrar window to add it to the flashable zip. Then copy the Signed recovery image and the Rom zip file to the phone memory card.

    Capture.png


    Capture6.png


    6. In the phone open Flashify and tap on Recovery Image. Then tap on 'Chose a file' and go to you memory card and select your signed Recovery image. After flash is complete you can tap on reboot and the phone will start in recovery mode. Since the image is signed there will not be any security errors.

    Screenshot_2015_11_15_23_07_35.png


    Screenshot_2015_11_15_23_07_51.png


    Screenshot_2015_11_15_23_09_01.png


    7. Now you can wipe data and flash your rom.

    Always make a CWM backup before performing those steps. And make sure you Sing (Bump) any image before flashing. If you don't it'll end on a security error. I'm not responsible of any data loss. I tested it with CWM, TWRP. Also CM11 and CarbonRom for P769 work fine.

    The credits of this goes to the developers of the Bump program. I'm just sharing how i did it on my LG L9 for those interested.
    View
    2
    E
    EdwinMoq
    puntoazul said:
    You are wrong... there is a new rom 5.1.1 for p769 Look here ---> http://xdaforums.com/optimus-l9/development/rom-cyanogenmod-12-1-t3271192
    Click to expand...
    Click to collapse
    Hehe. I was still struggling to make CM12.1 work when i made this post.
    View
    1
    mermigas
    mermigas
    Worked perfect on my daughters L760 locked
    Thanks
    View
    1
    E
    EdwinMoq
    bender_007 said:
    :) not sure why they didn't use it before

    If you need a one-click tell me :good:
    Click to expand...
    Click to collapse

    It would be nice to have an script to automatically sign images and modify the rom zip file. I don't have the skills to do that. I you could, that would be awesome.
    View
    1
    E
    EdwinMoq
    bender_007 said:
    Sure. But in future all boot/rec images would have to be signed(bumped)
    Click to expand...
    Click to collapse
    I know. I was thinking the if the script could unpack the ROM zip file, sign the boot.img and then repack the zip again. I know it can be done with the command line versit of 7zip. I'm know very experienced with batch scripts though.
    View

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