[Sprint LG G4] skytechja:
DETAILS ABOUT THE "ILAPO" HW FAULT:

The problem applies to all handsets sold until September last year (2015). After several months of using the phone, when the condition occurs, your phone is switched off and falls into the so-called Bootloop. This is the state when the phone is turned on and during the LG animation, system restarts over and over.

After each time the phone is turned on, you can turn it off only by pulling out the battery. In recent months, these cases occur frequently on the internet, and so penalized LG customers are all around the world (including Czech users with H815). This applies to all types of LG G4.

According to feedback from users all around the world, problems began to arise even on motherboards with revision 1.1 It is very important to check the three digits, located on the side of the device package. If you can see on the box first three numbers before the letters S/N 504, 505, 506, 507, 508 and 509, then you are affected by this vulnerability and you and your G4 can fall into irreparable bootloop as well.

NB: For me, the claim was rejected due to the oxidation of the mainboard. For this reason, I am striving for promoting this tutorial, since this is hidden HW from the manufacturer. This hidden HW fault was neither announced during the acceptance of goods nor in the device's description. In this case, the warranty is preserved. I would be more than happy if you will join me and help the LG G4 owners prevent the loss of any important data and subsequently resolve the problem.

THE TRUTH ABOUT THE "ILAPO" FAULT:

It was shown that hidden HW fault from the manufacter lies in the mainboard. Specifically, the chipset Qualcomm Snapdragon 808 MSM8992 (SoC) - CPU: 4x 1.44 GHz Cortex-A53 & 2x 1.82 GHz Cortex-A57. The actual error is then located in the dual-core 1.82 GHz Cortex-A57; quad core is fine and the error does not apply to it.

This is purely a HW defect that can be fixed by using the application "LGUP" which is used for flashing new firmwares. This application is intented only for use of internal purposes and LG authorized centers only.

Actually, the "fix" deactivates the dual-core CPU (1.82 GHz Cortex-A57) and in the addition, only one core will be kept working in the quad-core CPU (1.44 GHz Cortex-A53 - the remaining three cores will be also deactivated (however they can be turned on). I got the application from an user on an internet forum and I would like to share it with you.

https://www.youtube.com/watch?v=vnvD_ArfYZc

Lg g4... Ls991 zv6 ..... Sprint

I am yet to see any mention anything about the Sprint LG G4 owners.. ive even been in the specific forum and seems as though there is no support for us.

I would like to shut down the big cores so i can effectively back up my data etc...

anyways... for the LG G4 LS991 owners im currently running in zv6

i started experiencing the boot loop...

the first thing that i can say worked was putting it in the freezer for maybe about 10 minutes n then turning it on n leaving it in the freezer to boot.. . Just had to keep it really cold....

While in the freezer i was able to copy all my pics etc from internal to external memory.

so took it out n was tryig to use titanium to backup app data ( yeah my phone was rooted a long time ago)

while doing that, the phone got warm n went back to boot loop....

here is what i did next.....

- i dismantled the phone

- took out the main board

- removed the heat shields

- using my heat gun. I applied heat to the chips under the heat shield...

- when they got hot enough i used a cloth to hold the board n press down on the chips (Do not apply too much heat because u can burn them n render the phone useless)

- i did it couple times n the last time, i left the main board in my freezer for a few hours

- remove from freezer

- reassemble phone

- power on and allow to boot until screen goes off

- leave it let it sit there a few minutes (cores get warm every time u boot ur phone so u goto allow em to cool down after boot)

my phone has been up from that since now but i do not operate it as i normally would n i do not play any games on it so far... but it has allowed me to back up all my data etc.....

I will b monitoring the phone here on out to see what happens etc...

ive also decreased my screen brightness to the minimum. .. I am just trying everything to keep the temp of the phone down

I would love to get the tot files for the LS991 so that i could maybe shut down my big cores

Another suggestion I have after you actually get your phone up and running is to use a CPU control app to underclock your processor thereby slowing it down

No-frills CPU control is one such app.

curently testing as we speak....

Im trying to look out especially for the ls991 sprint users... but it applies to all LG G4 users