[G3 General] topet2k12001:
Flash

Open Android Terminal Emulator (install via Play Store if you haven’t done so).

Flash the “bump’d” Lollipop version boot.img by entering these commands (I am using the D858HK file as an example):

WAIT! I DON'T HAVE A "BUMP'D" LOLLIPOP VERSION BOOT.IMG!!! Or...I DON'T HAVE A WAY TO BUMP THE LOLLIPOP VERSION BOOT.IMG!!! HOW CAN I PROCEED FURTHER?

Fear not. :) In the first set of commands (writen in the box) below, just skip the third command. We will do something about it later BEFORE you reboot to Android. If you already have a Lollipop "bump'd" boot.img, then you can type the third command in the first set of commands (written in the box).

su
dd if=/dev/block/platform/msm_sdcc.1/by-name/boot of=/sdcard/boot.img [I][B](this makes a backup to your Internal Storage)[/B][/I]
dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/boot [I][B](writes “zeroes” to the partition to “wipe” it out)[/B][/I]
dd if=/sdcard/lollipop-bumped-boot.img of=/dev/block/platform/msm_sdcc.1/by-name/boot [I][B](flashes the “bump’d” Lollipop boot.img to the boot partition)[/B][/I]

Flash the “bump’d” TWRP recovery.img by entering these commands (I am using the D858HK file as an example):

su [B][I](no need to retype this if you did not exit from the previous Android Terminal session)[/I][/B]
dd if=/dev/block/platform/msm_sdcc.1/by-name/recovery of=/sdcard/recovery.img [B][I](this makes a backup to your Internal Storage)[/I][/B]
dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/recovery [B][I](writes “zeroes” to the partition to “wipe” it out)[/I][/B]
dd if=/sdcard/twrp-2.8.4.0_d858-signed.img of=/dev/block/platform/msm_sdcc.1/by-name/recovery [B][I](flashes the “bump’d” custom recovery to the recovery partition)[/I][/B]

Flash the Kitkat version aboot.img by entering these commands:

su [B][I](no need to retype this if you did not exit from the previous Android Terminal session)[/I][/B]
dd if=/dev/block/platform/msm_sdcc.1/by-name/aboot of=/sdcard/lollipop-aboot.img [B][I](this makes a backup to your Internal Storage)[/I][/B]
dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/aboot [B][I](writes “zeroes” to the partition to “wipe” it out)[/I][/B]
dd if=/sdcard/aboot.img of=/dev/block/platform/msm_sdcc.1/by-name/aboot [B][I](flashes the Kitkat version aboot.img to the aboot partition)[/I][/B]

Turn off the device.

Try to boot in recovery and confirm that you are able to enter TWRP. If yes, you’re good!

FOR THOSE WHO DON'T HAVE A "BUMP'D" LOLLIPOP BOOT.IMG:

Download the "Sharpening Mod Script" and put a copy to your Internal Storage (yes, you can plug the device while in TWRP and your computer should recognize it).

Flash the Sharpening Mod Script in TWRP (tap "Install" and then locate the Sharpening Mod Script in your Internal Storage, then to through the "wizard" installation steps).

The "Sharpening Mod Script" is a mod that allows you to adjust the "sharpness" level of the LG G3. Apparently, the LG G3 is "too sharp" to the point that displayed text shows a "ghosting" effect.

In the installation wizard, you can select how sharp you want the display to be. Lower value = less sharpness. I personally select zero (0) for "no sharpening at all".

The reason why we want to install the "Sharpening Mod Script" is because apparently, it also includes a script that will "bump" your Lollipop version boot.img! This solves your problem of not having a "bump'd" boot.img during the earlier steps!

Before you restart, make sure to flash the "Kitkat Boot Stack" zip. This will ensure that you will be able to use "Download Mode". Remember that it was initially created for D855. If you want to use it for your LG G3 variant, make sure to replace the ".img" files inside that zip with those of your LG G3 variant.

Now, exit TWRP by choosing “Reboot” and then “System”.

Test to see if you are able to boot normally to Android Lollipop. If yes, you’re good!

You’re done. Congratulations!