How To Repair Dead Lg G4

You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.

I got a non-working G4 (H815) from a friend - it doesn't start at all. He said it was bootlooping for some time and then it died completely. It is not in warranty anymore and it has SN starting with 505.
When I connect it to the PC, it appears as "Qualcomm HS-USB QDLoader 9008" or qhsusb_bulk in device manager. It doesn't start even in download mode or recovery, screen is not showing anything.

The only thing that helped was putting the phone to the freezer for a few hours - then Android started up to the welcome screen, but it froze a few seconds later and stopped working again.

Is there any chance that the phone can be fixed somehow by e.g. disabling big cores or baking the mainboard in the oven etc?

Last edited: Oct 16, 2017

I got a non-working G4 (H815) from a friend - it doesn't start at all. He said it was bootlooping for some time and then it died completely. It is not in warranty anymore and it has SN starting with 505.
When I connect it to the PC, it appears as "Qualcomm HS-USB QDLoader 9008" or qhsusb_bulk in device manager. It doesn't start even in download mode or recovery, screen is not showing anything.
The only thing that helped was putting the phone to the freezer for a few hours - then Android started up to the welcome screen, but it froze a few seconds later and stopped working again.

Is there any chance that the phone can be fixed somehow by e.g. disabling big cores or baking the mainboard in the oven etc?

http://tinyurl.com/g4fixitlist

9008 is the last step on the bootloop way to death. Check the above for temporary solutions and the one real fix.

Sent from my LG-H815 using XDA Labs

So I managed to get the phone working. I tried heating it up using hair dryer - witout any effect. Then I removed the mainboard and baked it in the oven (actually I have only halogen convection oven but it was enough) on 250°C for about 10 minutes, put some old thermal paste (over 10 years old cheap paste with quite poor thermal transfer) on CPU and eMMC chip (actually somebody obviously tried to repair that phone already in the past - there was some dried out white thermal paste on CPU already - and then sold it before it crashed again), I also put alluminium foil on top of the CPU and eMMC (to ensure that CPU is touching the heatsink and to increase the pressure on the chip - heatsink thermal tape would be better), assembled all back into the phone and it works. I was able to enter download mode, flashed Lollipop KDZ firmware using LGUP, it was bootlooping then, but after flashing TOT file to disable big cores it started to work properly (although very slowly). I was not happy with having just Lollipop, so I flashed Marshmallow KDZ using LGUP, followed by corresponding TOT file to disable big cores, unlocked bootloader, flashed TWRP, SuperSU, unlocked all 4 little cores and so far everything runs smooth, let's see how long it will last

My AnTuTu score with 4 cores is still 54500.

Unfortunatelly I don't have such equipment....

yesterday I passed the same thing to my LG G4 H815 Taiwan.
In my case with 1 hour in the freezer revived. And now it is working normally temporarily.

Mio is series 507 of the year 2015.
Lolipop 5.1 root, blocked bootloader.

Is it possible to disable big cores using the kernel auditor (root)?

I need my phone to continue working for two more weeks until I can get a new one.

edit:

kernel auditor root:

disable big core 5 , but not big core 6.
big core 6 reduced to max 966 mhz
litle cores 1,2,3 and 4 reduce to 966 mhz.
work.

Last edited: Oct 17, 2017

yesterday I passed the same thing to my LG G4 H815 Taiwan.
In my case with 1 hour in the freezer revived. And now it is working normally temporarily.
Mio is series 507 of the year 2015.
Lolipop 5.1 root, blocked bootloader.

Is it possible to disable big cores using the kernel auditor (root)?

I need my phone to continue working for two more weeks until I can get a new one.

edit:

kernel auditor root:

disable big core 5 , but not big core 6.
big core 6 reduced to max 966 mhz
litle cores 1,2,3 and 4 reduce to 966 mhz.
work.

I think freezer has much shorter effect than heat/baking - for me freezing helped only for a few seconds. But hopefully you will have more luck.
You can disable big cores in kernel adiutor, but it won't help you with bootloop - kernel adiutor activates its settings after booting, which is too late. You better flash TOT file (you don't need root or bootloader unlock for that as you do it in LGUP tool, for you it should be LGH815AT-00-V10g-GLOBAL-COM-NOV-18-2015+0_RECOVERY_5.1.tot) that disables all cores except one and then re-enable 3 little cores. I also saw some modified boot+recovery images for specific ROMs in the forum that could work too.

I have 12 hours of operation since the bootloop and for now everything works perfect.
current operating temperature 30 degrees Celsius for cores, and 26 degrees Celsius for battery.

If I start to have bootloop again I will place the tot with a single core. and finally the method of heating.

PD:
link for LGH815AT-00-V10g-GLOBAL-COM-NOV-18-2015+0_RECOVERY_5.1.tot , please !!

I think freezer has much shorter effect than heat/baking - for me freezing helped only for a few seconds. But hopefully you will have more luck.
You can disable big cores in kernel adiutor, but it won't help you with bootloop - kernel adiutor activates its settings after booting, which is too late. You better flash TOT file (you don't need root or bootloader unlock for that as you do it in LGUP tool, for you it should be LGH815AT-00-V10g-GLOBAL-COM-NOV-18-2015+0_RECOVERY_5.1.tot) that disables all cores except one and then re-enable 3 little cores. I also saw some modified boot+recovery images for specific ROMs in the forum that could work too.

Last edited: Oct 17, 2017

Thank you

MSM_Big_core_disable_tool_Rev8.0_20151224.zip

My H815 is definitely dead.

I worked well for 20 hours of low use, as soon as I armed it with the microsim and started to make calls came back the bootloop and then twice more that reboot never turned on again but despite having disabled the cores by of the recovery tot V10G.

next and last step:

Heating the motherboard.

My H815 is definitely dead.
I worked well for 20 hours of low use, as soon as I armed it with the microsim and started to make calls came back the bootloop and then twice more that reboot never turned on again but despite having disabled the cores by of the recovery tot V10G.

next and last step:

Heating the motherboard.

So good luck with baking...let us know your result

Well the result is known..

1) You will release toxic fumes so better never use the oven again afterwards
2) it may work for another while which can be 1 month or even half a year.
3) this is still a temporary solution and so it will happen again

This is all documented already and summed in my bootloop fix list..

Sent from my LG-H815 using XDA Labs

Well the result is known..
1) You will release toxic fumes so better never use the oven again afterwards
2) it may work for another while which can be 1 month or even half a year.
3) this is still a temporary solution and so it will happen again

This is all documented already and summed in my bootloop fix list..

Sent from my LG-H815 using XDA Labs

Which kind of toxic fumes get released and can they be cleaned?
After the phone dies after some time, will the baking help again?

I remember I baked my graphic card a few years ago and it did well after baking

Which kind of toxic fumes get released and can they be cleaned?
After the phone dies after some time, will the baking help again?
I remember I baked my graphic card a few years ago and it did well after baking

there is no "guarantee" that it really releases toxics but it can.. If so they will survive multiple cycles and no one knows when its safe again to use it for food. I mean you will not die the next day but i wouldnt take the health risks for a crappy manufactured phone.

I highly recommend doing this ONLY if you have no other option. Remember that heating a logic board to high temperatures can release toxic fumes. Don't use an oven you use for food preparation! Toxic fumes can leave residue in the oven and will be re-released upon reheating over many cycles!
Assuming LG's press release regarding the issue is correct and it is really a loose contact, this "fix" could actually work. Of course, only if the loose connection is a soldered connection. Though, it's controversial. You have to remember that the melting point for SMD solder is around ~350°C, or 662°F. So 358°F, or 181°C, is not nearly enough to actually re-solder a loose connection. My guess is that the loose solder point is only expanding due to the heat. There is no real reconnect. It might only be a matter of time until it also breaks. If you could locate the actual loose connection you could really re-solder it and have it fixed permanently.
I've done this on many many devices, including graphics cards, smartphone logic boards, PC mainboards etc. It only works if a soldered connection has a crack small enough that heat expansion is enough to gain reconnection. If there is a loose contact on the PCB or the "crack" in the solder is too big, it does not work. Also, if you really have a dead chip, this trick also won't (always) work.

so basically you can have luck and it will work for long but this all depends how good/bad your current soldering is.

sfX

so basically you can have luck and it will work for long but this all depends how good/bad your current soldering is.
sfX

Exactly. Mine died for good after I baked it the 2nd time. That was back in June 2016 IIRC. My device's production date was within the supposed bad batch period. Kudos to OP for including my warning message and actually caring for the users here.

Exactly. Mine died for good after I baked it the 2nd time. That was back in June 2016 IIRC. My device's production date was within the supposed bad batch period. Kudos to OP for including my warning message and actually caring for the users here.

How long did it work after the 1st baking?

About the toxic fumes, I doub't it will be affecting someone's length of life...we have toxic chemicals in many things these days If it is about mercury, it would be more toxical to breath it than eat it, so it would be good to at least exchange air in the room after the baking.

How long did it work after the 1st baking?
About the toxic fumes, I doub't it will be affecting someone's length of life...we have toxic chemicals in many things these days If it is about mercury, it would be more toxical to breath it than eat it, so it would be good to at least exchange air in the room after the baking.

2 days.

Never play down safety concerns. If you warn people you do that with many possibilities taken into account. While according to you these fumes shouldn't harm the average person, many of us have family and friends with weakened immune systems. This includes older people, pregnant women, infants, people with weakened immune response due to sickness and so on.

My point stands. You have been warned. Never use the same oven you bake electronics in for food preparation. In fact, stop baking electronics. It almost never works.

Last edited: Oct 20, 2017

2 days.
Never play down safety concerns. If you warn people you do that with many possibilities taken into account. While according to you these fumes shouldn't harm the average person, many of us have family and friends with weakened immune systems. This includes older people, pregnant women, infants, people with weakened immune response due to sickness and so on.

My point stands. You have been warned. Never use the same oven you bake electronics in for food preparation. In fact, stop baking electronics. It almost never works.

2 days only? Hmm, really quite short time...mine works for a week already (with 2 big cores disabled).

Yes, I agree that it is good to warn people against possible risks. However I am still curious about some proof and description of which fumes are released (tin and lead like during normal soldering, mercury, etc.?), but never mind...

2 days only? Hmm, really quite short time...mine works for a week already (with 2 big cores disabled).
Yes, I agree that it is good to warn people against possible risks. However I am still curious about some proof and description of which fumes are released (tin and lead like during normal soldering, mercury, etc.?), but never mind...

Core disabling wasn't a thing back then.

Here's a nice PDF from Techni-Tool, a company supplying the electronic production industry with soldering stuff, chemicals, tools and what not. It's not necessarily a paper from a scientific institution but I'd still take their word for it.

Similar threads