Temporary Fix for LG G4 bootloop issue(lengthens life)

XeniX_Force · Jul 27, 2017

Hello everyone.
You all might have read in the xda news that @XCnathan32 fixed the Nexus 6p and now also the Nexus 5 bootloop issue (same as on our G4s) by disabling the big faulty cores and running the phone on only the small ones. Now our beloved dev @steadfasterX has come up with a similar fix for our G4.
it works by flashing modified boot and TWRP image onto the LG G4 so that it only works on the small four cores

UPDATE: Tested and found working by @the_naxhoo on his H815

Requirements

An unlocked G4
@steadfasterX 's FWUL for ease and required tools (lglaf)
Patience and prayers (optional though)

NOTE: the attached files are only for the T-Mobile variant which had 20o software before boot looping and the International H815 (BGR) variant which had 20g software before bootlooping

Guide:

(A)For unlocked devices that can access Fastboot
Access Fastboot mode by using the following method:

Pull out battery then connect usb cable, press volume down, put battery back while keeping volume down pressed

If you just reached the Fastboot mode, Congrats. Now execute the following commands in fastboot

Code:

fastboot flash boot boot.img
fastboot flash recovery twrp_4cores_3.1.1-1-g4.img

Now you have a kernel and twrp with max 4 CPUs and the faulty CPUs disabled. Enjoy your resurrected phone.

(B)For Devices that can not acess Fastboot(unlocked only)

For a backup of your existing data you need an external SD Card big enough for a full backup of your device (64 GB if you want to backup the /data partition - otherwise you will be fine with 8 GB) best is to format the SD card with ext4 !! fat32 will fail for backup

For just flashing a boot image any SD card will fit..

1)extract both files you downloaded(see attached files) and put them on the SD card
2)boot FWUL and login
3)put the external SD card in your phone
4)boot phone to download mode and connect it to your PC with FWUL running
5)in FWUL find the folder LG on the desktop and open it
double click on the lglaf (auth) icon
6)you should see the lglaf shell now. Type in the command:

Code:

uname -a

(it should print out the line with your current kernel version which just indicates that you're connected)
7)mount external SD:

Code:

mount -t ext4 /dev/block/mmcblk1p1 /storage/external_SD

8)Now backup first (recommended but optional):

9)Now flash:

Code:

dd if=/storage/external_SD/boot.img of=/dev/block/mmcblk0 seek=491520 bs=512

Code:

dd if=/storage/external_SD/twrp_4cores_3.1.1-1-g4.img of=/dev/block/mmcblk0 seek=573440 bs=512

Now you have a kernel and twrp with max 4 CPUs and the faulty CPUs disabled. Enjoy your resurrected phone.

Please test and leave comments

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Update: File for h815 20i is here: https://xdaforums.com/g4/general/fix-lg-g4-bootloop-issue-t3647538/post73282829
File for h815 20p is here: https://xdaforums.com/g4/general/fix-lg-g4-bootloop-issue-t3647538/post73610856
File for H811 20r is here: https://xdaforums.com/g4/general/fix-lg-g4-bootloop-issue-t3647538/post73636261

Stransky · Jul 27, 2017

Any chance of getting this for international H815 version with H81520g firmware?

Sent from my iPad using Tapatalk

XeniX_Force · Jul 27, 2017

Stransky said:
Any chance of getting this for international H815 version with H81520g firmware?

sure I'll update the OP with it soon

XeniX_Force · Jul 27, 2017

Stransky said:
Any chance of getting this for international H815 version with H81520g firmware?

please give me the link to the v20g kdz firmware

skdubg · Jul 27, 2017

XeniX_Force said:
please give me the link to the v20g kdz firmware

hi,
Here you find it all:
https://lg-firmwares.com/lg-h815-firmwares/
ist there a way to disable the big cores on any rom (original/custom) for all time?

XeniX_Force · Jul 27, 2017

skdubg said:
hi,
Here you find it all:
https://lg-firmwares.com/lg-h815-firmwares/
ist there a way to disable the big cores on any rom (original/custom) for all time?

there might be @steadfasterX is currently working on this. he'll tell you after that hopefully

Stransky · Jul 27, 2017

XeniX_Force said:
please give me the link to the v20g kdz firmware

As posted by (skdubg) and select GBR version.

steadfasterX · Jul 27, 2017

skdubg said:
hi,
Here you find it all:
https://lg-firmwares.com/lg-h815-firmwares/
ist there a way to disable the big cores on any rom (original/custom) for all time?

Atm the method is ROM specific. That means I need a direct link or the EXACT file name to the used kdz. E.g. H815 has several country versions.

Disabling the cores on any ROM means modifying aboot which is not an option because even when your device is unlocked the try may soft or hard brick.

Instead once I have the time I will make a flashable TWRP zip for this which patches the boot image after flashing a ROM but this is a manual task everytime after flashing a ROM.

Stransky said:
As posted by (skdubg) and select GBR version.

Perfect thx.

Sent from my LG-H815 using XDA Labs

XeniX_Force · Jul 28, 2017

Anyone with an bootlooped H811 who can try this?
The file for h815 will be uploaded soon

steadfasterX · Jul 28, 2017

Stransky said:
As posted by (skdubg) and select GBR version.

find attached the patched boot image for your ROM version.
just to mention it again: the modded twrp image is highly recommended to flash as well bc TWRP will make use of all cores it can find when backing up/restore

when your device is unlocked AND you have fastboot access you can just do a

Code:

[COLOR="Blue"]fastboot flash boot boot_4cores.img
fastboot flash recovery twrp_4cores.img[/COLOR]

The download mode way I described in the OP is required when you cannot access fastboot and for locked devices. I will try to create a KDZ out of this but atm this is the way to go then.

I cannot say for sure that this way will soft brick locked devices or not. it should not but i cannot test it..!!
It mainly depends on the fact if the whole boot image gets verified or just the kernel + initrd.
afaik its not the whole boot partition... so it should work with the download mode way even on locked devices.

@XeniX_Force : attach the file and fastboot cmds to the OP as well pls.

.

XeniX_Force · Jul 28, 2017

Stransky said:
Any chance of getting this for international H815 version with H81520g firmware?

The OP has been edited with a fastboot method. you can either use it or the download mode method to try and revive your G4 your requested file has been attached please try and report to us as soon as possible

rustybronnco · Jul 28, 2017

The only fix for a G4 rebooting is the remove the LPDDR3, reball and replace it.

XeniX_Force · Jul 28, 2017

rustybronnco said:
The only fix for a G4 rebooting is the remove the LPDDR3, reball and replace it.

not necessarily. the problem is with the bigger cores. why replace ram?

rustybronnco · Jul 28, 2017

The issue is failed solder joints between the SOC and the LPDDR3. Disabling cores will not keep it from occurring.

XeniX_Force · Jul 28, 2017

rustybronnco said:
The issue is failed solder joints between the SOC and the LPDDR3. Disabling cores will not keep it from occurring.

but we tested on the_naxhoo's bootlooped phone and it's back to working

rustybronnco · Jul 28, 2017

https://en.wikipedia.org/wiki/LG_smartphone_bootloop_issues

When officially acknowledging the bootloop issues with the G4, LG stated that it was caused by a "loose contact between components";

---------- Post added at 02:41 PM ---------- Previous post was at 02:35 PM ----------

XeniX_Force said:
but we tested on the_naxhoo's bootlooped phone and it's back to working

Applying pressure to the chip may also bring it back to a non-boot loop condition.

My G3 has a credit card 'shim' between the LPDDR3 and the housing. It cured? the fad out to black for a period of time. They also blue or green screened as well. On the G4 it shows up as a boot looping or stop (stuck) booting condition. My G4 is currently at LG awaiting a motherboard.

XeniX_Force · Jul 28, 2017

rustybronnco said:
https://en.wikipedia.org/wiki/LG_smartphone_bootloop_issues

---------- Post added at 02:41 PM ---------- Previous post was at 02:35 PM ----------

Applying pressure to the chip may also bring it back to a non-boot loop condition.

My G3 has a credit card 'shim' between the LPDDR3 and the housing. It cured? the fad out to black for a period of time. They also blue or green screened as well. On the G4 it shows up as a boot looping or stop (stuck) booting condition. My G4 is currently at LG awaiting a motherboard.

understood

the thread has been renamed
our phone is hopeless

rustybronnco · Jul 28, 2017

Don't get me wrong, this may help extend the life of certain units. But as they say, it might be just a matter of time before the problem rears its ugly head once again.

https://www.reddit.com/r/lgg4/comme...boot_looping_g4_replaced_for/#bottom-comments

Stransky · Jul 28, 2017

XeniX_Force said:
The OP has been edited with a fastboot metho,chave d. you can either use it or the download mode method to try and revive your G4 your requested file has been attached please try and report to us as soon as possible

Hi
Thanks for the files. Have a new problem in that my G4 has stopped bootlooping, in fact it is not doing anything now.
Have tried another battery but no response, Was on the Lifes Good screen and it suddenly
went blank and it will not boot to anything. Tried spare battery and connected to charger but nothing.
Any ideas?

steadfasterX · Jul 28, 2017

Stransky said:
Hi
Thanks for the files. Have a new problem in that my G4 has stopped bootlooping, in fact it is not doing anything now.
Have tried another battery but no response, Was on the Lifes Good screen and it suddenly
went blank and it will not boot to anything. Tried spare battery and connected to charger but nothing.
Any ideas?

yea bootloop is the first stage. next one is what u describe. send it to repair.
there are good chances that it went into QDL 9008 mode. Just connect it to your PC and watch unknown devices in your device manager (or type lsusb on linux) and see what happens.

.

.

Temporary Fix for LG G4 bootloop issue(lengthens life)

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