[G2 Q&A, Help & Troubleshooting] d00lz:
UPGRADE/DOWNGRADE bootloaders/recovery/kernels and flash ROMs​

THIS GUIDE WAS WRITTEN FOR DORIMANX KERNEL AND LG G2, BUT THE STEPS SHOULD BE THE SAME FOR ALL.

JUST MAKE SURE YOU USE THE RIGHT FILES FOR YOUR DEVICE!!!!!!!!!!!​

I WILL REPEAT: MAKE SURE YOU USE THE RIGHT FILES FOR YOUR SPECIFIC PHONE!!​

Files for LG G2: http://www.dorimanx.com/LG/

NOTE: This is for D802, if you have another variant just substitute "flash KK bootloader" or "flash JB bootloader" with the following (from OP):

"I have created ONE flash zip with all that needed for D802, including stock stuff from 20D KDZ image.

find for your model, extract needed partitions as in my zip, replace and flash.

too hard??? leave it alone and keep using JB bootloader till you find mind power to do it".

This means: download the D802 KK bootloader flash file, download your model's kdz, extract the files needed (same as in the D802 KK booloader flashfile), replace them in the zip and flash or install everything manually.

Same for JB bootloader zip file.

If you are reading this then you know how to do this. If not then just stick to JB or buy a D802.

IMPORTANT: if you do NOT know how to unbrick a phone through download mode and installing custom KDZ and all the rest of it then please don't blame anyone. There are threads in xda for un-bricking.

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First I repeat the steps for installing BUMPED KK bootloader:

Phone status: non-bumped recovery, non-bumped kernel, JB bootloader, stock-based ROM

You want to: install KK bootloader

1) reboot to recovery

2) flash bumped TWRP 2.8.1.1

3) reboot to recovery

4) flash Dorimanx 9.1 kernel

5) flash KK bootloader

6) reboot to system

You now have: bumped recovery, bumped kernel, KK bootloader, stock-based ROM

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IMPORTANT: After you have installed BUMPED TWRP, you NEVER need to replace it with non-BUMPED version. It works with JB bootloader too.

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Installing a new/different stock-based JB ROM (or dirty flash or clean flash existing ROM) but

want to keep KK bootloader

:

Phone status: Bumped recovery, bumped kernel , KK bootloader , stock-based ROM (ie: you just did all the steps above)

1) reboot to recovery

2) flash stock-based JB ROM as per OP (inc wipes if necessary)

3) flash BUMPED dorimanx 9.1 kernel BEFORE REBOOT TO SYSTEM

4) reboot to system

You now have: bumped recovery, bumped kernel, KK bootloader, stock-based ROM

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Returning to JB bootloader with your current ROM:

Phone status: Bumped recovery, Bumped kernel, KK bootloader , stock-based ROM

1) reboot to recovery

2) flash JB bootloader

3) reboot to system

You now have: bumped recovery, bumped kernel, JB bootloader, same ROM as before

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Installing JB AOSP ROM (with non-bumped kernel):

Phone status: Bumped recovery, Bumped kernel, KK bootloader , stock-based ROM

1) reboot to recovery

2) flash JB bootloader

3) flash JB AOSP ROM as per OP (inc wipes if necessary)

4) reboot to system

You now have: bumped recovery, non-bumped kernel, JB bootloader, AOSP ROM

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Installing stock-based JB ROM and go to KK bootloader from AOSP ROM:

Phone status: Bumped recovery, non-bumped kernel , JB bootloader , ANY ROM

1) reboot to recovery

2) flash stock-based JB ROM as per OP (inc wipes if necessary)

3) reboot to system

4) install ROM, let it settle for 5 minutes

5) reboot to recovery

6) flash BUMPED dorimanx 9.1 kernel

7) flash KK bootloader

8) reboot to system

You now have: bumped recovery, bumped kernel, KK bootloader, stock-based ROM

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PS: thanks to vpro97 for checking and Dorimanx of course for making all this happen :)