[G3 General] topet2k12001:
Hi [MENTION=3093263]RustyPwns[/MENTION],

What are you interested in? Just root? Or root AND installation of TWRP? If it's root only, then you don't have to downgrade the bootstack. ImageprepGUI offers the option to only root the device. If your concern involves installation of TWRP, please read on.

On the contrary, ImageprepGUI was created to assume that the user is currently running Lollipop. If you have time, please read more through the thread and you will see that a lot of users started the process running on Lollipop.

You can extract the needed .img files (for example, laf.img and aboot.img which is needed in the ImageprepGUI procedure) from a TOT file via the TOT/KDZ extractor. There's actually a dedicated thread for it since I am not the creator of that tool, but I just embedded/added it to ImageprepGUI for convenience.

Even if the procedure starts off running on Lollipop (which it currently does), you will need the Kitkat bootstack; there's no way around it. No need to find Lollipop versions of the bootstack since you will not need them anyway.

The idea of rooting on Lollipop for LG G3 (regardless of the different guides/threads that you will read) is that you will need to downgrade the bootstack ONLY to Kitkat (specifically, aboot.img and laf.img ONLY). All the other partitions are supposed to be on Lollipop. So you can use the files shared by the person you are referring to (the one who uploaded Kitkat bootstack).

The reason why this is the case, is because the discovered process is to sign another partition (technically, image) with a digital signature (and that image is boot.img). This "signing" is called "bumping" or "bump". The purpose of "bump" is a means (or workaround) to the technically-locked bootloader of the LG G3. So "bump" takes care of that.

However, "bump" creates a new problem. Now that boot.img is "bumped" (signed with a Kitkat digital signature), the problem with a full/default/stock Lollipop setup is that it will complain (not boot and will give you a "boot certification verify" error) that the other images (laf.img = which provides "Download Mode" and aboot.img = the Android bootloader) are on Lollipop since they bear a "Lollipop" digital signature. So the solution is to replace aboot.img and laf.img to those coming from a Kitkat firmware. Once that is achieved, all three images (boot.img, laf.img, and aboot.img) are now bearing the same digital signature (Kitkat). Everyone "shakes hands" and proceeds to boot the device to Android.

Therefore, there are two approaches to achieve this: you can either fully downgrade to Kitkat first (which is the old, original method)...or you can use ImageprepGUI as the procedure has developed/progressed through time. No need to follow the steps on the second/third post; just watch the YouTube video (I also uploaded the video file so users can download and play/pause it to their convenience) and just follow the video step-by-step.

Not sure how much more detail is needed when an end-to-end, start-to-finish video tutorial is already provided. I know that XDA is an international forum (spoken/written language can be a barrier to communication - I'm not a native English speaking person myself) and in my opinion, nothing can get more detailed with a "show me" approach - a video - as it solves language/comprehension barriers (it's going to be as easy as "monkey-see, monkey-do"). If that doesn't suffice as far as being detailed, I don't know what else can be done to satisfy all needs of all users.

Also, this thread is turning one year old on the 8th. A lot has changed from the time that root was not available due to the "locked bootloader" and we started off by doing this manually. I just happened to devote time to automate some stuff to make the process less manual. Amidst all of that, I kept the original, very manual steps that involved fully downgrading to Kitkat and is available in the thread (OP). That method still works to this day but yes, it is inconvenient because one has to downgrade first. But again, a lot of progress has been made and ImageprepGUI is one of the results of that progress so users can choose the new method or the old method.

There are actually other methods that you can try, and respective threads are available here in XDA. Whether the other methods are more difficult or easier is going to be a different discussion; the point is that the underlying process being followed by all available methods is the same: the bootstack will have to be downgraded to Kitkat so that when boot.img is "bumped", the device will boot to Android.