Bootloop and random reboot fix - LG G Flex 2

I've been seeing some threads about some some people experiencing lots of random crashes, random reboots and bootloop. From what I've seen for some it's caused by a faulty battery, but for some others it seems like a hardware problem similar to the LG G4 bootloop problem. I also have read that a hard drop can cause a similar issue. I have been experiencing this with my G Flex 2 but only after installing the AT&T 5.11 update for H950. I don't know if it's a manufacturing problem or something that happens from a random drop since I have dropped my phone in the past but not very hard.
I experienced just about every odd symptom with this phone after the update. After a reset things seemed fast and stable but after installing apps it would start having problems. Usually just a random reboot followed by the phone starting with optimizing apps almost every time. A couple of times it even got stuck doing boot loops. Usually after about a month of random reboots eventually mobile network would stop working and only a complete reset would fix it.
To me this sounded similar to the LG G4 problems my wife had on two of her G4s before they would finally only boot loop. Which is caused by a bad solder connection to the processor. This is also something that happened to many older laptop NVIDIA graphics processors in the past. I've been able to fix laptop graphics cards permanently by reflowing the solder with Solder flux so I thought I would give it a try on my G Flex 2. Now this isn't very complicated but you have to be careful. I've tried it on my dying G Flex 2 and so far it's been running for almost a week without a single crash or reboot any more. Something else that's interesting is that it's actually running cooler and consuming less battery than before.
Basically I pulled the phone motherboard out and pulled the RF shields off (which came off pretty easily by just pulling them up with a small flat head screwdriver). Then I put some flux on top and around the main processor and voltage regulator just in case that was an issue as well. After that I grabbed my heat gun but only used it to melt and spread the flux around the components I wanted to reflow. If you don't have a heat gun a blow dryer should work as well. I made sure the heat gun didn't get any hotter than 160F by pointing it at a piece of aluminium foil and then using a temperature gun to measure the temperature of the aluminium. I would then adjust the heat gun until it was at around 160F. Once I got the flux spread around really well I would preheat the oven to 385F. Once warm I would put the motherboard with the main processor facing up on top of baking sheet with a large piece of aluminum folded multiple times. Others use aluminum foil balls and set them at the corner but I was afraid a chip underneath might fall off. Make sure the motherboard is laying flat and not at an angle. Then I set the pan in the oven for 7 minutes. Once the 7 minutes were up I pointed my temperature gun at the processor and it measured at 401F so hotter than the oven was set at. I also have a convection oven so I'm not sure if this may have made it warmer than expected. At this point I just turned the oven off and cracked it open until it cooled. Once cooled I used pure 100% alcohol to clean some of the flux off. You can also reheat the flux on the board to help you clean it off it it's too hard. After this I just reinstalled the RF shields and put the phone back together. There's always a chance that this may cause more damage so make sure to backup your data. If you're out of your warranty there's nothing to lose by trying this and if you are in warranty I don't even know if LG would notice. I just hope that maybe this can help someone with similar symptoms.
Here's a few links on some of the information and things I used for this.
I followed the steps from a post on reflowing the solder on a LG G4 here:
http://forum.xda-developers.com/g4/help/diy-h815-usa-variant-hardware-boot-loop-t3311623
Here's a video showing the process of reflowing a G4 but with an expensive temperature precised heat gun. I wouldn't recommend reflowing with just a regular heat gun since they're not as consistent:
https://www.youtube.com/watch?v=cadWAgYcmGc
I also used the Solder FLUX below:
https://www.amazon.com/gp/product/B00425FUW2/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Here's the type of temperature gun I used:
https://www.amazon.com/Etekcity-Las...06763&sr=1-2&keywords=temperature+reading+gun.

hey, nice thorough fix thread. Also, you're the same guy that made the enhanced thermal engine file! Wow, you're really good at this, aren't you XD? I'm gonna try to replace my battery to see if it fixes my bootlooping (my model is the H959 one)... If it doesn't, I'll translate your thread and show it to a technician to see if he can do it, since it would mean the battery's not the problem in my case. Can I do that, or do you not give me permission? Also, I'm not sure if you updated your thermal engine files later on after the first page of the that thread you made, have you made better ones? ALSO (last question, I promise) do you think this bootlooping might have been cause by charging it with a power bank (I'm charging it on the 5V 2.1A port, the other is 5V 1.0A)? Because it wasn't long after I started using it my phone started bootlooping, plus people said in the bootlooping forum (the one you linked to this thread) that using non-LG chargers was what bootlooped their phones, and even one guy said he used a power bank. Sorry for the massive amount of questions, but I would appreciate if you could answer them ~

Yes you can show this to who ever you want if it helps. One way to know if it's your battery is to have it plugged when using the phone and if you still get bootloops then it's most likely the phone not the battery.
I have experimented making some more aggressive and some slightly more conservative thermal files, however I never gained much and sometimes ran worse then my thermal files I originally posted.
No I don't think a powerbank is an issue with causing bootloops. I actually have two G Flex 2 phones. one has the default thermal file and the other is modified. On both phones I've used three different powerbanks including one that charges at 2.1 amps. Yet the phone I used less with the default thermal file is the one that started having problems. I could be wrong but I think even if you had a really bad powerbank I don't think it would damage the phone primarily. I think it could damage the charging regulator and perhaps the battery. The battery and regulator should buffer a lot of the electricity going to the phone.
The fact that I could fix my phone by reflowing the board kind of shows that in my case the problem was with connections not damage from a charger.
I've already heard of quite a few G Flex 2s, V10 and G5s, having bootlopoop issues. Not as many as the G4s but this seems to have have happened to a lot of LG smart phones made within the last year and a half. LG has also admitted that the G4 problem was caused by bad solder connections to the CPU and RAM .
Well I hope you can figure out your phone. Good luck

Here's something else that G4 users say stopped the bootloops. It's not a fix but more of a test. Try disabling all the big cores on the phone. This made G4 users phone work, but at the cost of performance. But it's worth a shot. If it works then you'll know for sure your problem is caused by a solder connection problem.

probaina said:
Here's something else that G4 users say stopped the bootloops. It's not a fix but more of a test. Try disabling all the big cores on the phone. This made G4 users phone work, but at the cost of performance. But it's worth a shot. If it works then you'll know for sure your problem is caused by a solder connection problem.
Click to expand...
Click to collapse
thank you for answering... My phone stops bootlooping when charging, so it must be the battery. Still, thank you very much for responding... I'll try disabling the big cores if after I change the battery the problem still remains.

Hey there mate,
As you can expect my Flex 2 decided to go into the infinite boot loop after 1 year and and a couple months of ownership.
I came upon your re-flux fix guide after countless hours researching for a way to hopefully fix the Flex 2 myself and not forking more $$$ over to the crooks @ LG.
Was hoping you could give me a pretty detailed update as to how the Flex 2 you operated on has been up to date. Crossing my fingers the guide you posted is a pretty long term fix.
Thanks and let me know
:good:

Had random powerdowns with battery not discharged. One morning the phone would not go past LG boot screen. No playing with battery /charging helped. Found this guide, used rosin flux from radioshack, 385F in the oven for 7 minutes, cooled for an hour, cleaned rosin residue with rubbing alcohol. The phone booted and is working. Will post updates if anything goes wrong with it. Thanks OP.
Update:24 hours still going strong. This is good enough to recover data, already.
Update:14 days later, everything was working fien, left the phone in the carin the open sun, for a couple of hours, it must have baked while charging, I came back it was hot and off and wont respond to power, nor power/volume down buttons. Thought it was done, but couple hours later, it booted up, battery almost fully drained. Fix is still in.

Mine also atfirst went to optimising apps and now it doesn't even turn on please
probaina said:
I've been seeing some threads about some some people experiencing lots of random crashes, random reboots and bootloop. From what I've seen for some it's caused by a faulty battery, but for some others it seems like a hardware problem similar to the LG G4 bootloop problem. I also have read that a hard drop can cause a similar issue. I have been experiencing this with my G Flex 2 but only after installing the AT&T 5.11 update for H950. I don't know if it's a manufacturing problem or something that happens from a random drop since I have dropped my phone in the past but not very hard.
I experienced just about every odd symptom with this phone after the update. After a reset things seemed fast and stable but after installing apps it would start having problems. Usually just a random reboot followed by the phone starting with optimizing apps almost every time. A couple of times it even got stuck doing boot loops. Usually after about a month of random reboots eventually mobile network would stop working and only a complete reset would fix it.
To me this sounded similar to the LG G4 problems my wife had on two of her G4s before they would finally only boot loop. Which is caused by a bad solder connection to the processor. This is also something that happened to many older laptop NVIDIA graphics processors in the past. I've been able to fix laptop graphics cards permanently by reflowing the solder with Solder flux so I thought I would give it a try on my G Flex 2. Now this isn't very complicated but you have to be careful. I've tried it on my dying G Flex 2 and so far it's been running for almost a week without a single crash or reboot any more. Something else that's interesting is that it's actually running cooler and consuming less battery than before.
Basically I pulled the phone motherboard out and pulled the RF shields off (which came off pretty easily by just pulling them up with a small flat head screwdriver). Then I put some flux on top and around the main processor and voltage regulator just in case that was an issue as well. After that I grabbed my heat gun but only used it to melt and spread the flux around the components I wanted to reflow. If you don't have a heat gun a blow dryer should work as well. I made sure the heat gun didn't get any hotter than 160F by pointing it at a piece of aluminium foil and then using a temperature gun to measure the temperature of the aluminium. I would then adjust the heat gun until it was at around 160F. Once I got the flux spread around really well I would preheat the oven to 385F. Once warm I would put the motherboard with the main processor facing up on top of baking sheet with a large piece of aluminum folded multiple times. Others use aluminum foil balls and set them at the corner but I was afraid a chip underneath might fall off. Make sure the motherboard is laying flat and not at an angle. Then I set the pan in the oven for 7 minutes. Once the 7 minutes were up I pointed my temperature gun at the processor and it measured at 401F so hotter than the oven was set at. I also have a convection oven so I'm not sure if this may have made it warmer than expected. At this point I just turned the oven off and cracked it open until it cooled. Once cooled I used pure 100% alcohol to clean some of the flux off. You can also reheat the flux on the board to help you clean it off it it's too hard. After this I just reinstalled the RF shields and put the phone back together. There's always a chance that this may cause more damage so make sure to backup your data. If you're out of your warranty there's nothing to lose by trying this and if you are in warranty I don't even know if LG would notice. I just hope that maybe this can help someone with similar symptoms.
Here's a few links on some of the information and things I used for this.
I followed the steps from a post on reflowing the solder on a LG G4 here:
http://forum.xda-developers.com/g4/help/diy-h815-usa-variant-hardware-boot-loop-t3311623
Here's a video showing the process of reflowing a G4 but with an expensive temperature precised heat gun. I wouldn't recommend reflowing with just a regular heat gun since they're not as consistent:
https://www.youtube.com/watch?v=cadWAgYcmGc
I also used the Solder FLUX below:
https://www.amazon.com/gp/product/B00425FUW2/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Here's the type of temperature gun I used:
https://www.amazon.com/Etekcity-Las...06763&sr=1-2&keywords=temperature+reading+gun.
Click to expand...
Click to collapse

Is Your Flex 2 still working.Please help!
:crying::crying:
probaina said:
I've been seeing some threads about some some people experiencing lots of random crashes, random reboots and bootloop. From what I've seen for some it's caused by a faulty battery, but for some others it seems like a hardware problem similar to the LG G4 bootloop problem. I also have read that a hard drop can cause a similar issue. I have been experiencing this with my G Flex 2 but only after installing the AT&T 5.11 update for H950. I don't know if it's a manufacturing problem or something that happens from a random drop since I have dropped my phone in the past but not very hard.
I experienced just about every odd symptom with this phone after the update. After a reset things seemed fast and stable but after installing apps it would start having problems. Usually just a random reboot followed by the phone starting with optimizing apps almost every time. A couple of times it even got stuck doing boot loops. Usually after about a month of random reboots eventually mobile network would stop working and only a complete reset would fix it.
To me this sounded similar to the LG G4 problems my wife had on two of her G4s before they would finally only boot loop. Which is caused by a bad solder connection to the processor. This is also something that happened to many older laptop NVIDIA graphics processors in the past. I've been able to fix laptop graphics cards permanently by reflowing the solder with Solder flux so I thought I would give it a try on my G Flex 2. Now this isn't very complicated but you have to be careful. I've tried it on my dying G Flex 2 and so far it's been running for almost a week without a single crash or reboot any more. Something else that's interesting is that it's actually running cooler and consuming less battery than before.
Basically I pulled the phone motherboard out and pulled the RF shields off (which came off pretty easily by just pulling them up with a small flat head screwdriver). Then I put some flux on top and around the main processor and voltage regulator just in case that was an issue as well. After that I grabbed my heat gun but only used it to melt and spread the flux around the components I wanted to reflow. If you don't have a heat gun a blow dryer should work as well. I made sure the heat gun didn't get any hotter than 160F by pointing it at a piece of aluminium foil and then using a temperature gun to measure the temperature of the aluminium. I would then adjust the heat gun until it was at around 160F. Once I got the flux spread around really well I would preheat the oven to 385F. Once warm I would put the motherboard with the main processor facing up on top of baking sheet with a large piece of aluminum folded multiple times. Others use aluminum foil balls and set them at the corner but I was afraid a chip underneath might fall off. Make sure the motherboard is laying flat and not at an angle. Then I set the pan in the oven for 7 minutes. Once the 7 minutes were up I pointed my temperature gun at the processor and it measured at 401F so hotter than the oven was set at. I also have a convection oven so I'm not sure if this may have made it warmer than expected. At this point I just turned the oven off and cracked it open until it cooled. Once cooled I used pure 100% alcohol to clean some of the flux off. You can also reheat the flux on the board to help you clean it off it it's too hard. After this I just reinstalled the RF shields and put the phone back together. There's always a chance that this may cause more damage so make sure to backup your data. If you're out of your warranty there's nothing to lose by trying this and if you are in warranty I don't even know if LG would notice. I just hope that maybe this can help someone with similar symptoms.
Here's a few links on some of the information and things I used for this.
I followed the steps from a post on reflowing the solder on a LG G4 here:
http://forum.xda-developers.com/g4/help/diy-h815-usa-variant-hardware-boot-loop-t3311623
Here's a video showing the process of reflowing a G4 but with an expensive temperature precised heat gun. I wouldn't recommend reflowing with just a regular heat gun since they're not as consistent:
https://www.youtube.com/watch?v=cadWAgYcmGc
I also used the Solder FLUX below:
https://www.amazon.com/gp/product/B00425FUW2/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Here's the type of temperature gun I used:
https://www.amazon.com/Etekcity-Las...06763&sr=1-2&keywords=temperature+reading+gun.
Click to expand...
Click to collapse

Farqaleet said:
:crying::crying:
Click to expand...
Click to collapse
Thought I'd post an update on this. Recently my GFlex2 started having the same symptoms again which I'm not surprised. I have also done this fix with two LG G4s which actually need a lot more heat to get them working again. On the two G4s I fixed I ended up going up to 435F and those two have been working for over six months now. I plan on raising the temperature on my GFlex 2 motherboard this time and I'll post on how long it lasts this time.
One thing I find really interesting is that on my Gflex 2 running Android 5.01 this crashing and random reboot problem doesn't happen. It only happened when I upgraded my second Gflex 2 to version 5.1. From the very first boot after the upgrade, this problem happened. This seems to be a similar problem that happens with the Nexus 5X as well.

probaina said:
Thought I'd post an update on this. Recently my GFlex2 started having the same symptoms again which I'm not surprised. I have also done this fix with two LG G4s which actually need a lot more heat to get them working again. On the two G4s I fixed I ended up going up to 435F and those two have been working for over six months now. I plan on raising the temperature on my GFlex 2 motherboard this time and I'll post on how long it lasts this time.
One thing I find really interesting is that on my Gflex 2 running Android 5.01 this crashing and random reboot problem doesn't happen. It only happened when I upgraded my second Gflex 2 to version 5.1. From the very first boot after the upgrade, this problem happened. This seems to be a similar problem that happens with the Nexus 5X as well.
Click to expand...
Click to collapse
Any update please after raising the temperature?

hbahaie said:
Any update please after raising the temperature?
Click to expand...
Click to collapse
Well my G Flex 2 didn't like raising the temperature very much. The phone seems to not crash any more but I think it damaged battery temperature sensor. Sometimes it thinks the battery is too cold and other times it things it's suddenly way too hot. Oddly enough the battery temperature sensor is on the motherboard or something. I can tell the readings are bogus since the battery temperature suddenly jumps by a lot. Maybe on the G Flex 2 at least it's better to use a heat gun directly on the CPU chip instead of baking it above 385F.
I'm going to try to reflow it again and see if maybe just some sensors need to be reflowed. I think I can also tell the thermal config file to ignore max battery temperatures. Although that probably isn't the safest thing to do.

Hi all. Has anyone tried this wakelock fix?
Some YouTube users commented the fix helps.

probaina said:
Thought I'd post an update on this. Recently my GFlex2 started having the same symptoms again which I'm not surprised. I have also done this fix with two LG G4s which actually need a lot more heat to get them working again. On the two G4s I fixed I ended up going up to 435F and those two have been working for over six months now. I plan on raising the temperature on my GFlex 2 motherboard this time and I'll post on how long it lasts this time.
One thing I find really interesting is that on my Gflex 2 running Android 5.01 this crashing and random reboot problem doesn't happen. It only happened when I upgraded my second Gflex 2 to version 5.1. From the very first boot after the upgrade, this problem happened. This seems to be a similar problem that happens with the Nexus 5X as well.
Click to expand...
Click to collapse
Looks like I was wrong. I just had some flux in the battery port. I cleaned it up and it's working great again.
So basically the first fix at 385f worked for about 6 months than it started to reboot often and later turned into boot loop.
This time I decided to go set my oven at 410f and using my laser infrared thermometer I kept checking on the CPU temperature until it reached 420f. Took about 10 minutes to get there.
Another thing I tried that I read works well on the G3 boot loop problem, is to use a piece of wood to push down on the processor with a few pounds of force. Once I pulled the board off the oven it quickly cooled to 380f at that point I used a stick with a flat end to push down on the processor. I would recommend to be careful and press down with no side movement for a few seconds. This can hopefully squish all the solder to an even height and hopefully make a more reliable fix.
So far after a few days the phone has been working great.
Also on the LG G4 I baked to 435f so far has been working perfectly fine for 10 months which is actually oddly longer then the three new G4s my wife got lasted before this fix.

Help!!!
Hi I am a big noob when it comes to all of this. Today my phone (G Flex 2 H955) went into a bootloop when I disconnected it from the charger. It has randomly restarted several times in the past few months but this time it was just bad (until I stumbled upon this thread I never even knew it could be a hardware issue, just assumed unstable OS was to blame). I even factory reset the thing while plugged into the charger, but it didn't make a difference. My phone restarts even when plugged into the charger but not as often and doesn't go into a bootloop like it does now when disconnected. I was thinking I'd try out what you have detailed here. I went through the video but found it all a bit lacking in detail for a noob like me. This is the first time I am gonna do anything like this. Initially I thought I'd just go to some repair shop and show them this thread, but here in India, you can't really trust everyone's work ethics and you'd never know, the guy might say yes yes I'll do it, and then botch it up cause he doesn't have the right equipment or the interest. Another thing that is different is the availability of good quality stuff to do the job, and information on what is what (atleast for someone like me who literally has no idea what is what). Could you please help me do this thing on my own. I have to cause I'm in college and just can't afford a new phone or shoddy repairs on this one at the moment. From the video you linked, I surmised that all I would need is a temperature precise heat gun and flux fluid.
Are there any more precautions I need to keep in mind? If that is the stuff I need to buy to do this job properly, then can I just clean out a syringe and use it to extract the flux fluid is it super sensitive to impurities? What kind of air speed should I start off with for how much time? Do I just set it straight to 200C (385F) or do I get there incrementally? Is there anything else I might be missing out? I am super desperate and super interested to get a response. Looking forward to it. Sorry for the annoying questions!
Cheers!

Hi,
Had a problem with the Flex 2 where it would not turn on. originally unclipping the battery for a while would get it back working but then even that did not work.
Anyway have tried the oven trick several times and it so far it has worked - get about 3 months before I have to repeat. I don't use flux/remove the heat shield. I just take the main board out, wrap it lightly in tinfoil and put it in a digital over heated to 220 degrees. I "bake" for 20 minutes, take it out and let it cool down. I get another 3 months or so from the phone.
What seems to cause to not to turn on is if it is left on the charger for too long!.
Hope this helps someone.
W.

I bought a bootlooping G Flex 2 off eBay, swapped in a new battery, and it ran a month or two just fine. Had issues again though, so I tried a new charging port board - didn't help. Did the "light" baking fix above this morning, 220°F for 15 minutes in foil. Reassembled and successfully booted again. :good: Will save up for flux and do the more intense reflow procedure if bootloops come back.

Hmm,
I'm gonna chime in with a fix that worked for me that didn't require me to bake the snapdragon 810 chip or the voltage regulator.
Instead here's exactly what I did.
1. Disassemble your phone until you get to the motherboard. Remove the RF shield around the Snapdragon 810 chip. Remove thermal pad on the 810 chip.
2. Wrap every component in aluminum foil or kapton tape (Google this). I used kapton tape (may post pics later). The parts I didn't cover was the 810 and voltage regulator. Place board on a cool surface.
3. Heat the hot air gun to 450F.
4. Start the clock. From about 1-2 feet slowly lower the hot air gun until you are a few cm from the 810 chip. When you reach the chip, make small circles at the center of the chip to melt the solder balls. Do this all until 2 minutes are up.
5. Once 2 minutes are up, slowly raise the hot air gun back about 1-2 feet from the chip.
6. Repeat steps 4-5 for the voltage regulator.
7. Allow the motherboard to cool (I waited for 1 hour).
8. Obtain some good Thermal Pads. I don't remember the exact material I used but they were industry-grade top of the line ones.
9. Cut the Thermal Pads to the shape of the Voltage Regulator and the 810 chip.
10. Use 70% IPA Isopropyl Alcohol to clean the motherboard after removing the aluminum foil or kapton tape covering on the motherboard.
11. Place the Thermal Pads on the chips.
12. Snap the RF shield back on the motherboard. You will likely have to press hard on it due to the Thermal Pads being thicker than the shield.
13. Reassemble your phone, plug in your battery for a few minutes and boot up your phone. It will take some time to boot up. Be patient!

PhantasmRezound said:
I bought a bootlooping G Flex 2 off eBay, swapped in a new battery, and it ran a month or two just fine. Had issues again though, so I tried a new charging port board - didn't help. Did the "light" baking fix above this morning, 220°F for 15 minutes in foil. Reassembled and successfully booted again. :good: Will save up for flux and do the more intense reflow procedure if bootloops come back.
Click to expand...
Click to collapse
Sorry, should have mentioned I do the "bake" at 220 degree Celsius (not really light) glad it worked for you.
I have found it lasts for approx. 3 months and tends to die when I have forgotten to take the phone off charge (charging for approx. 36 hours).
W.

This method revived my LS996!

Related

Having battery charging issues? Read this...

Just an FYI.............
So for the last several months my Tbolt has not wanted to charge past 50-60% no matter what I do. Even charged in a stand alone charger it would still only read 50-60%. It actually was charging fully but just wouldn't read the voltage correctly.
I decided it was a hardware issue so last week I bought a used Tbolt on ebay that was in pieces. I took that motherboard and put it in my phone and voila FULL CHARGE!! BUT when setting the phone up the wifi refused to work. It kept giving "error" or "unable to scan", that really pissed me off. I tried several radios and roms with no luck.
So tonight I decided to reflow my original motherboard and see if it would fix a faulty solder joint that it might have causing it not to read the voltage right. I put it in the oven at 385 for about 10 minutes then opened the oven door and let it cool down. I'll have you know that the original motherboard is now reading the correct voltage!!! Halleluyer!!! Everything else seems to work fine too, except..........
A few things to do before you decide to stick it in the oven, remove both cameras because it melted the lense on both, and even tho it didn't mess up my earpiece speaker or loudspeaker I would recommend removing those also.
Next I'm gonna reflow the ebay one and see if that fixes the wifi issue. If it does then awesome!!
nxslt1 said:
Just an FYI.............
So for the last several months my Tbolt has not wanted to charge past 50-60% no matter what I do. Even charged in a stand alone charger it would still only read 50-60%. It actually was charging fully but just wouldn't read the voltage correctly.
I decided it was a hardware issue so last week I bought a used Tbolt on ebay that was in pieces. I took that motherboard and put it in my phone and voila FULL CHARGE!! BUT when setting the phone up the wifi refused to work. It kept giving "error" or "unable to scan", that really pissed me off. I tried several radios and roms with no luck.
So tonight I decided to reflow my original motherboard and see if it would fix a faulty solder joint that it might have causing it not to read the voltage right. I put it in the oven at 385 for about 10 minutes then opened the oven door and let it cool down. I'll have you know that the original motherboard is now reading the correct voltage!!! Halleluyer!!! Everything else seems to work fine too, except..........
A few things to do before you decide to stick it in the oven, remove both cameras because it melted the lense on both, and even tho it didn't mess up my earpiece speaker or loudspeaker I would recommend removing those also.
Next I'm gonna reflow the ebay one and see if that fixes the wifi issue. If it does then awesome!!
Click to expand...
Click to collapse
Creative home remedy to fix the solder joints. Nicely done.
but, most people arent willing to put their mobo in the oven

[Q] Stuck on booting up Samsung screen

Hi,
My Note Pro 12.2 P900 64gb is now stuck on the samsung screen of booting up and I am wondering if anyone can help me figure out what to do next.
I was experiencing the flickering issue for the last two weeks which got progressively worse and eventually caused random rebooting. One time last week it started booting slower and then it wiped out some widgets on my start screen and the apps in touchwiz but most everything else was OK. Then yesterday it would not boot up past the samsung screen. It charges up OK, and I can get to Odin where it asks if I want to load another operating system by holding power and vol up. But unless it is plugged in, just holding power off puts it in a boot loop.
The other part is if it is stuck and I hold power off it usually vibrates twice before boot looping.
I rooted the tablet when I got it, but still run stock touchwiz, I just needed some rooted apps namely LMT pie controls.
Can anyone please point me towards what to do next. Thank you very much for your help.
I guess wiping data and factory reset is your only solution right now
I shall warn you you could lose your data so I hope you already have a backup!
And also I've read that lollipop fixed flickering issue in p900 devices
I hope everything goes well for you
Good luck
hey there, you are not the only one, check this post. it seems is somethig related to battery issues
http://forum.xda-developers.com/showpost.php?p=61785158&postcount=14
minionhunter said:
The other part is if it is stuck and I hold power off it usually vibrates twice before boot looping.
Can anyone please point me towards what to do next. Thank you very much for your help.
Click to expand...
Click to collapse
When power on, try pressing on the back, near the center with your hand. to see if it can boot normally,
Keep pressing while power on. if it works I will tell you what causing this problem.
https://www.youtube.com/watch?v=VeSG0hHpAG8
here you can look by the minute 2:30 where the connector is located, basically under the samsung logo. I'm not doing tests yet because i have a busy day ahead
Thank you all for the responses. Holding down the back while powering on does not help. I do have the flickering thing and that started leading up to this. Lay night I took it the battery and disconnected it for a half hour and that did not help. Looking at the connections with a 20x hand lens did not reveal any cracks.
I don't remember how to wipe the data off the device, I got it right when it came out rooted it with cf root and never got around to twrp. All I wanted was LMT and Xposed. I never even updated the OS.
If anyone can help walk me through this to get it running again I'll send you a green poetic skin used once or a white well used GumDrop hideaway case I tested for work. I just would like to get this running instead of needing to purchase a new one.
Thank you again. Sincerely.
Flickering screen is caused by cracked battery connector which cannot be seen under magnified glass. Re solder will fix it, trust me I did fix some of them
Beut said:
Flickering screen is caused by cracked battery connector which cannot be seen under magnified glass. Re solder will fix it, trust me I did fix some of them
Click to expand...
Click to collapse
So resolder the 6 posts connecting the battery connector to the motherboard? Is there anything special I need to do that, just my soldering iron with a fine tip and solder? Anything special I need about the solder or do I need a wik or anything? The last time I did any soldering work was about 25 years ago.
Also will this fix the bootlooping and hanging on booting up at the Samsung word on the screen? If it is not going to fix that problem, maybe I should look at something else first.
Thank you very much again for your help.
Sincerely
minionhunter said:
So resolder the 6 posts connecting the battery connector to the motherboard? Is there anything special I need to do that, just my soldering iron with a fine tip and solder? Anything special I need about the solder or do I need a wik or anything? The last time I did any soldering work was about 25 years ago.
Also will this fix the bootlooping and hanging on booting up at the Samsung word on the screen? If it is not going to fix that problem, maybe I should look at something else first.
Thank you very much again for your help.
Sincerely
Click to expand...
Click to collapse
First, pressing the battery connector help your tablet to boot is a confirmation of cracked battery connector solders. 90% flickering problem is from cracked battery connector. 10% is bad battery. You should fix the battery connector first as it's major defect seen in many Samsung tablets. Re solder is simple, apply flux, then heat these pins and add more solders as possible to secure these pins. Even new main board, this connector will crack just after 3 or 4 months depending how you use your tablet, especially with who using it on their laps. The main board sits on a flexible LCD and only 3 screws to hold it to the frame at 2 speakers. You don't need to remove the main board, just disconnect your battery and re solder the connector from the top.
Be careful as this connector is very close to other components. Trust me, this re work will fix this problem as I have seen in some cases, battery jumps up from 8% to 45% after the re work, other cases pressing the battery connector help the tablet to boot or stop flickering.
This person applied the fix and succeed.
http://forums.androidcentral.com/sa...screen-flickering-problems-3.html#post4473418
I have the Note Pro 12.2 and I had this same screen flickering issue. It would start to flicker at first around the 38% mark. I did research online and found this thread and many others. I tried the software fixes like the enabling of Developer Mode and screen brightness and other tries, but to no avail. When I pressed on the back of the tablet, the screen flickering would stop but then shortly return. So I saw the fix of trying to raise the motherboard which worked for about 2 weeks, then the screen flickering did return. It would then start to flicker around the 58% battery level mark and when it got down to around 26%, the tablet would shut down. When I plugged it in, it would show battery level of 0%, then quickly jump back up to the 26% mark when it shut itself down. So then by this time, I saw more of this thread and now was shown the soldering of the battery connectors. I had soldering equipment, but it was too large for this repair as these 6 pins are very close together. So I went to the hobby shop and purchased new equipment for about $30 with a smaller pin to be able to do this. Now, I am not an electronics guy and my past experience was replacing two bad capacitors on my Plasma TV when it went bad. That was the extent of my experience to date. So I opened up the back of my tablet and soldered the 6 pins again and the screen flickering has not returned. I am on my 5th battery cycle from 100% all the way down to 2% and the screen flickering and shutting itself down has not returned. Some people have said an electronics guy will do this for you for around $30. Well, I spent the $30 and did it myself. I want to thank the people for posting the solutions here as the soldering worked for me.
And from this post, a confirmation that repair center will do the same thing to fix flickering , auto reboot, auto shut down.....etc...all problems caused by cracked battery connector ( Connector Header ):
http://forum.xda-developers.com/showpost.php?p=58943998&postcount=74
Ok I'll try to resolder it this weekend and report back. I think that my pertinent problem is that I have both the battery issue AND another problem that the tablet won't boot up at all but I will try the battery fix first and see what happens. Then I will report back.
Thank you very much for your suggestions.
Your feedback is very important as I see many " Hit and Run " users, they get the solution they need but never post back. Your first priority is fixing the battery connector, then next is the battery if problem persists.
This is a hardware defect I have seen in many Samsung tablets: battery capacity fluctuation, quick discharge, auto reboot, auto shutdown.......all come from battery connector . Read the threat Flickering Screen you'll see others try all solutions but never work because they don't know this is a hardware problem coming from this tiny connector.

Can a (going bad) battery cause the phone to boot loop?

Original battery.
Stock 5.01 (still) rooted.
The battery is fully charged.
LG logo, AT&T logo (and sound) then reboot. Repeat.
Just under a year ago, I bought 2 new batteries with external charger (Power Bear) because I felt the original battery was not lasting as long as it had previously. The new batteries seemed to deliver about the same time as the original so since then I've been rotating the three- charging using the external charger exclusively.
Around six months ago, I noticed that when the battery would reached to about 6,7 or 8%, I would be at risk for a "spontaneous" reboot, then a boot loop as described above. (this can occur w/the new batts too)
I quickly determined it was time to swap the battery and that's it.
In the past two months, THAT behavior has began to sometimes manifest itself with between 15-19% battery life. I thought, 'OK. Move on, the battery gauge is probably not accurately reflecting what's really left in the battery any longer.'
NOW, the original battery, though fully charged, is causing the circular reboot upon being inserted.
Can a battery "go bad" in this type of manner? Without really exhibiting significant "performance loss" (read: usage time)?
I'm thinking the orig battery can no longer deliver the proper current, or something like that.
To be clear, the other two batts work fine.
Anyone ever heard anything like this?
*edit:
An interesting piece of info: If I leave the phone plugged in to the charger, it DOES boot up fine and stay up. The second I PULL OUT THE PLUG, it reboots, and so on....
Yes it’s very very common. And is usually a battery issue. When it comes to the G3 anyway
Sent from my iPhone using Tapatalk
Did you ever figure it out? If it's not a battery issue maybe it's an LG motherboard issue, like everyone else who's had their G3 close to 4 years. In that case, do what I do, stick the LG G3 motherboard ONLY into the OVEN and BAKE it for 10 mins @ 360 degrees. Believe it or not, baking solves many of the problems, not charging, boot-loop, not turn on, blue screen, freeze ups, etc. I have 2 LG G3's, 1 AT&T and 1 TMobile, that I do this with. I can go weeks without having to bake them again but then sometimes when I'm driving and need my phone the most, it dies, won't even turn on. So it's not a permanent cure because it'll happen again, no doubt, the question is, how long...I laughed when someone said oh, just bake the motherboard. Well, come to find out the type of solder they used on the motherboard melts at a lower temperature so when it gets too hot some chips lose their connections, thus by baking it I guess it reseats the chips. Hey, it works every time after I bake it so I can't knock it.
Either way, give it a shot, it can't hurt your motherboard and if it fixes the problem, at least you'll know how to fix it and think about getting a new phone, like myself, lol. Instructions are quite simple.
1...Take back off
2...Battery out, Sim out, SD out
3...small philips head, remove 12 screws from back, the screw next to camera does not have to be removed.
4...remove both rear-housing assemblies
5...Remove motherboard by disconnecting the rear camera connector, front camera connector, lcd screen connector, and the touchscreen connector.
6...Now remove the motherboard, hold back the connectors when lifting the motherboard out. Do not bend or break the connectors.
7...Take the motherboard, piece of tinfoil or parchment paper (i prefer tinfoil), lay the tinfoil on a baking sheet/cookie sheet, and then place the motherboard on the tinfoil with
the CPU facing up. Pre-heat the oven to 360 degrees, when it beeps, put it in for 10mins. After 10 mins, pull it out, turn your oven off, let motherboard sit for 15 mins and put the phone back together. Be careful snapping the connectors back into their places.
8...Be surprised when your phone still actually works after doing something like that to it.
I actually just baked mine again last night.
Good luck.

Major issues due to wrong (batt) temp reading

Hope someone can help me out.
Got water inside my U11, so took it apart, cleaned with alcohol, dried.
Now I can sometime switch the phone on, and then it's working perfectly, charging is hit and mis, mostly mis.
It seems the issue is that the phone thinks the battery temperature is (usually) around MINUS 20 (celcius).
Heating the phone temporary solves this and makes it possible to charge.
Now I have replaced the battery, but the issue remains.
I am pretty convinced that the sometimes not switching on also has to do with some thermal protection.
So I am hopeful that with solving the low temp reading I will be able to completely fix the phone.
My question thus is, does anyone know how to fix this?
My best bet would to replace the charging PCB.
But I am reluctant to throwing to much money in it with no result so I would like some advice first.

How to check dissembled Pixel 4a Mainboard?

Hi all,
I ditched my phone in water.
I disassembled the whole phone, cleaned everythign with IPA and dried it afterwards. Now I would like to check if the mainboard is still working.
I connected the battery, display and usb port to the mainboard and plugged a charger in -> no response (display black, no vibration, sound etc)
I assume that the batterie is completly dead as it discharged until it turned off.
Is this aready a clear sign for a broken mainboard or does it only boot when fully assembled? Just want to avoid to put more effort into the phone, e.g. replacing the battery etc if its already lost...
Thanks in advance!
Dry for at least 72 hours in a warm dry room with a fan on the mobo. The BGA chipsets can dry slow.
Isopropyl is hygroscopic so it's important to remember it may attract some moisture from the air while drying. Use only >92% or greater, 96% is best. Submerged the board in it for a couple minutes while moving it around.
Battery needs to be charged and good for the phone to boot.
Out of circuit the mobo especially is sensitive to ESD damage. Use your best judgment but more assembled is better than less assembled unless very familiar with the device.
Thanks for the reply! Phone is "drying" for two month now as I was already considering as "lost" after disassembling and no luck with first checks. But before getting the new 6a, I want to give it a last try Was just 7 month old when I dropped it :/
When I plugged the charger in, there was no sign of charging. So not sure if the batterie is broken or if its coming from the board, or both.
A new battery is quite expensive just for a test / to find out more is damaged.
Helikoptermann said:
Thanks for the reply! Phone is "drying" for two month now as I was already considering as "lost" after disassembling and no luck with first checks. But before getting the new 6a, I want to give it a last try Was just 7 month old when I dropped it :/
When I plugged the charger in, there was no sign of charging. So not sure if the batterie is broken or if its coming from the board, or both.
A new battery is quite expensive just for a test / to find out more is damaged.
Click to expand...
Click to collapse
If the battery sat near its auto shutdown voltage for 7 months it's DOA.
A charger likely won't supply enough current to boot.
The fact that it does nothing when connected to the charger is a bad sign.
Check for loose connectors, bent connector pins, etc.
Examine the mobo (power section especially) and connector pins closely for corrosion damaged caused by electrolysis.
Since you can't see the BGA pads if there's corrosion there...
Water exposure; power off immediately and pull the battery asap to limit damage. Salt or brine water is a death sentence though.
Anhydrous isopropyl alcohol is an excellent drying agent but it and any solvents can't be used around LCD's; it will irreversibly poison them.
LCD's are vented to atmosphere on the sides...
blackhawk said:
Water exposure; power off immediately and pull the battery asap to limit damage. Salt or brine water is a death sentence though.
Click to expand...
Click to collapse
Thats true, happened at work so I could do anything for the whole day and in the evening it was already dead. With some random screen on and offs during the day and "booting into fast mode" or something similar during the day.
Phone was not reacting to switch it off normally, screen was black and buttons did not react either
blackhawk said:
Anhydrous isopropyl alcohol is an excellent drying agent but it and any solvents can't be used around LCD's; it will irreversibly poison them.
LCD's are vented to atmosphere on the sides...
Click to expand...
Click to collapse
A thats interesting, I was already thinking that some water went inside the screen. Because I have quite some dark areas on the screen, which increased in size the first days. Looked like water got pulled in. Was hoping that when the phone gets warm again it will disappear...
blackhawk said:
The fact that it does nothing when connected to the charger is a bad sign.
Click to expand...
Click to collapse
Yeah, have the same feeling. Very unlucky as it was just rain water in a not perfectly closed rain jacket...
Will check the connectors and cables again but was already quite sure that they are all clean
Helikoptermann said:
Thats true, happened at work so I could do anything for the whole day and in the evening it was already dead. With some random screen on and offs during the day and "booting into fast mode" or something similar during the day.
Phone was not reacting to switch it off normally, screen was black and buttons did not react either
A thats interesting, I was already thinking that some water went inside the screen. Because I have quite some dark areas on the screen, which increased in size the first days. Looked like water got pulled in. Was hoping that when the phone gets warm again it will disappear...
Click to expand...
Click to collapse
That sucks. Prompt battery disconnect* can save electronics (flooded cars sometimes too).
LCDs are sort of witchy. The spot may or may not disappear over time. Have an old S4 that got sunbaked while charging. The display had multiple issues, barely usable. Thought it had fried drivers. Strangely the longer it sat unused the better it got. 3 years latter it almost 100%.
*Lol, 3 years ago I dropped my Buds case in a full cup of coffee, cream and sugar of course. It promptly sank to the bottom like a lead weight.
The Li is spot welded in. Immediately tore it apart, flushed with RO water, then with anhydrous isopropyl, allowed to dry for a day.
It's still working normally today. A drank that cup of coffee afterwards too

Categories

Resources