[G3 General] topet2k12001:
Troubleshooting and Q&A

Q: No radio signal (wifi, 2G/3G/4G/LTE)

A: The Lollipop modem.img was not flashed because you forgot to rename the modem_XXXXX.img as modem.img. Or, you forgot to put modem.img in the "flash2" folder. Remember, the Flash2Modem.zip script is programmed to look for modem.img in the "flash2" folder.

A: You have various versions (Kitkat and Lollipop) of boot.img, modem.img, and system.img and you accidentally mixed them up. Make sure that you organize your files properly (put them in folders) and then try the process again.

Q: I get the “certificate verify” error when booting to Android.

A: The Lollipop boot.img was flashed successfully, but was not “bump’d” because you forgot to flash the Sharpening Script Mod BEFORE booting to Android as per the tutorial. Also, make sure as well that at the end of the Sharpening Mod Script, un-select the box for rebooting. You should reboot from TWRP’s main reboot menu and not from the Sharpening Script Mod.

A: You have various versions (Kitkat and Lollipop) of boot.img, modem.img, and system.img and you accidentally mixed them up. Make sure that you organize your files properly (put them in folders) and then try the process again.

A: You got adventurous and flashed the Lollipop aboot.img to the device.

1. Hopefully you had a “bump’d” TWRP before you followed this procedure.

2. Extract the Kitkat aboot.img from your Kitkat KDZ (the Kitkat version that you were on prior).

3. Power off the device.

4. Boot into TWRP (yes you can boot to TWRP even with that error – as long as you had TWRP installed prior).

5. Plug the device to your computer. The device will open/show in Windows File Explorer. Transfer the Kitkat aboot.img to your Internal Storage.

6. Power off and then boot to TWRP again, and then reflash aboot.img.

7. You may end up booting properly to Android but losing “bump’d” hence, you will lose TWRP. That’s fine.

8. Assuming you are able to boot properly to Android, install Android Terminal Emulator.

9. While in Android, install the “bump’d” TWRP via Terminal Emulator, following the steps from the “Bump” thread.

10. Power off the device and boot into TWRP.

11. Flash the Sharpening Mod Script. It will “bump” your Lollipop boot.img properly.

12. Reboot to Android.​

Q: After following the procedure, the phone boots to LG "Life's Good" but after that, I don't see the splash screen/boot animation. Instead, I just see a black screen with "security error" written in the middle of the screen.

A: The Lollipop boot.img was not flashed because you forgot to rename the boot_XXXXX.img as boot.img. Or, you forgot to put boot.img in the "flash2" folder. Remember, the Flash2Boot.zip script is programmed to look for boot.img in the "flash2" folder.

Q: I seem to go into a “boot loop” to TWRP.

A: Common mistake is that people accidentally flash recovery.img to the “Boot” partition, or flashing boot.img to the “Recovery” partition. Reflash the proper Image file to the appropriate partition. If the problem persists, @autoprime created a flashable zip that will fix this problem.

Q: I get the “certificate verify” error when booting to Download Mode, or I can’t boot to Download Mode.

A: You got adventurous and flashed the Lollipop aboot.img, laf.img, or sbl1.img (or other partitions that were not covered in this tutorial) to the device. See long answer from above.

Q: How do I "bump" my custom recovery (TWRP)?

A: D858HK users: you can download a copy from the "Requirements" section in Post #1. Popular variants: the more popular variants (like the D855 - International variant) are very well supported; please search for TWRP as a keyword under the LG G3 section. Less popular variants: there are two (2) tools that you can use. One is "Bump Windows version" and another is "Open Bump". It's easy; just drag-and-drop your custom recovery image (TWRP) to bump.exe (for Bump Windows) or open_bump.py (for Open Bump).

Q: Okay, now I have "bump'd" my custom recovery. How do I install it? I obviously can't flash it via TWRP because I don't have it installed yet.

A: There are two ways to do it. One is done manually. You need to be rooted (Kitkat) and should have Android Terminal Emulator installed. And then you will have to enter some commands. The other way is to do it via "Flashify" (it's an app). For details and instructions, please visit the official "Bump" thread; Post #1.

Q: Do I need to have a custom recovery (TWRP) installed? There are not a lot of custom ROMs for the D858HK anyway so it doesn't make any sense.

A: Yes, you do. Even if you do not intend to install custom ROMs. Installing custom ROMs is just one of the features of a custom recovery such as TWRP, but remember - its main purpose is to provide you with advanced options of recovering your device in the event of a "brick" situation. I have had many instances when I totally "bricked" my device and was saved because I created a full system backup using TWRP. Oh, and make sure that you have installed TWRP and created a full system backup while you are in Android Kitkat!

Q: Do I need to "bump" my current (Kitkat) boot.img and flash it to the device too, before I follow this tutorial?

A: So I downgraded back to Kitkat and tried upgrading again. One with a Kitkat "bumped" boot.img, and another without (stock). In both scenarios, the device was upgrade properly (with root, "bump'd" boot.img, and "bump'd" TWRP). I therefore conclude that it doesn't matter. When you update to Lollipop as per this tutorial, you will end up overwriting the Kitkat boot.img with the Lollipop boot.img and "bumping" anyway (at the part where you flash the Sharpening Script Mod).

Q: There are new threads for rooting Lollipop without downgrading. Here and here. How is your method different?

A: Yes I have read them as well. Great guides, actually. :) However, those are strictly for rooting only. No custom recovery, no "bump". If you want to maintain "bump'd" boot.img and "bump'd" recovery.img (custom recovery such as TWRP), you will still end up having to follow the steps in this guide - downgrade to Kitkat first, extract Lollipop KDZ firmware, and flash only system.img, boot.img, and modem.img. If you are not tinkering around and are confident enough that you won't do adventurous things with your device, it's okay not to have a custom recovery. Therefore, merely rooting your device would be sufficient. In my case, I have "bricked" my device multiple times and was saved by custom recovery, so I would say I need it.

I asked the question in one of the threads: http://xdaforums.com/showpost.php?p=59328257&postcount=9

But eventually, I already saw the answer. Fellow XDA member (Recognized Contributor) @6ril1 also confirms this: http://xdaforums.com/showpost.php?p=59325441&postcount=55

So, I created another guide (within this thread - see First Post for the link) on how to achieve that. :)

Q: After following the how-to guide, I lost my Download Mode! Whenever I try to go to Download Mode, it just hangs and show a "Certificate Verify" error!

A: This happens when you followed the "No Downgrade" approach and did not flash Kitkat versions of the "Boot Stack" (persist.img, dbi.img, laf.img, sbl1.img, rpm.img, and tz.img). The how-to guide for "No Downgrade" approach has been updated accordingly to include this step. Those who followed the "Kitkat Downgrade" approach do not need to flash these image files anymore because they are already on Kitkat version.

There is an easy way to do this. XDA member @6ril1 created a TWRP-flashable zip file to automate it. The zip file was originally created for the D855, but you can replace its contents with ".img" files for your LG G3 variant. Just follow the instructions in the link provided.