[LG G Flex 2] probaina:
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://xdaforums.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.