[AT&T LG V10] hoang51:
tl;dr: My chronology of the infamous LG V10 boot loop death which got repaired under LG's unannounced extended 15 months warranty. Important lesson learned is make sure to back up all the phone's valuable data (even though I technically didn't lose anything critical).

01/03/2017: I finally experienced the infamous boot loop of death with my AT&T LG V10 yesterday (01/02/2017). The boot loop I encounter isn't due to flashing gone bad or wrong, but due to regular use. My phone wasn't excessively overheating at the time, but I do know that the metallic ring around the power/finger print sensor was warm due to surfing the internet at the time on Chrome. I do have a tempered glass on the phone and a slim translucent plastic cover to protect my phone. What happened was that my phone suddenly just powered off the display screen. I thought the phone just experienced a force close and forced reboot, not that I ever experienced one with the V10, but other Android phones before (i.e., very old ass Android phones). But I waited for the phone to boot up, but it never did. I tried to reboot the phone and then that's when it got to the home screen and locked up. Ever since then, reboots failed to get pass the AT&T logo, but could pass the LG logo.

I've already tried the refrigerator/freezer trick to cool down the phone, but it appears that I'm passed that stage where the phone would not boot pass the LG logo or AT&T logo. The more I tried to get the phone to boot up, the more it will just stall or reset at the LG logo, or refuse to boot up (i.e., speed up its death). Even the charging screen once showed, no longer reaches the charging stage where it shows the percentage of the battery's power remaining through the wall charger or being plugged into a computer laptop. Pulling the battery and letting the phone sit idle (to cool down the internal circuits?) for a while will allow it to come back to life with the boot loop problem or the ability to charge the battery via a computer's USB port. I tried charging with the wall adapter, but that forces the phone to boot up, and render the phone useless thereafter, so I elected to charge the phone via computer.

My AT&T LG V10 (H900 variant) is on Android 6.0 (H90021w00). It's not rooted anymore due to upgrading to Android 6.0 (I updated back in November 2016 here) without issue and wasn't abused (e.g., phone dropped, water damage) for it to cause the boot loop of death. The hardware version (H/W) is 1.0 with the SKU 6084A. Battery manufacturing date appears to be 2015.11.07 (D). The OEM package boxing has DHHS Code MC1, manufactured date of 12/2015 and made in Korea.

I wanted to try and save some data off of my phone, but the phone couldn't stay on life support long enough. Of course, fastboot won't allow me to save data (it's design is to write data only). I did manage to put the phone into download mode (i.e., phone powered off, hold down volume button and plug in USB cable from computer) one time and try to flash an upgrade of Android 6.0 firmware H90021w00 with LG Up, but it failed somewhere after 10%.

Good thing I have Google Photos backing up all my photos and videos, and nothing critical resides on my phone other than auto logins. I'll just have to change all my passwords soon enough if my phone has to be taken away for warranty. I wanted to at least save data and do a data wipe to make sure that nothing falls into the wrong hands. But I now can't do any of the two. I called the nearest AT&T corporate store, but was directed to one that has a warranty center. I will be on my way to an AT&T corporate store later tonight that has a warranty center. Just doing so to avoid traffic. I know my phone has the usual 1 year warranty, and speaking to the AT&T corporate store with the warranty center, I was told that I have at least 80 something days left of warranty. So good thing I'm not screwed and can at least get a replacement phone.

Currently the phone is sitting on my desk charging at a slow ass rate and up from fluctuating anywhere between 12% and 21% to a now whopping 30% power capacity. I want to at least demonstrate the boot looping to AT&T personnel and it's not due to physical damage or water damage. I'll report back what's happening with my situation so that way, anybody else who experienced this situation will have something to go by.

Update 01/04/2017: I read through the freezer trick thoroughly this time and the entire thread. I decided to try it again, but this time, I left the phone in the freezer for a short time (half an hour or so) without the battery. After time elapsed in the freezer to cool down the phone, I plugged in the USB to the phone while having my laptop near the refrigerator with LG Bridge loaded and ready to back up, and then put in the battery. Lo and behold, the phone did manage to boot up all the way to the lock screen, due to various sound cues from the phone (AT&T logo) and USB connectivity (from Windows 7). However, when I tried to unlock the phone, that's when it froze and rebooted. After that, it hit the boot loop and won't get as far as the initial try. So I'll keep trying to revive my phone long enough to get some data off of it and wipe it clean. I still have time with warranty, so I'm in no hurry. Besides, I attempted warranty processing last night and missed the opening as the warranty department closed early.

Update 01/11/2017: I managed to get my LG V10 phone to boot up further than the freezer trick by utilizing the hair dryer trick here. Basically, what the video shows is that one must take a hair dryer, blow dry on the highest heat setting to the bottom of the backside phone up to the point where the phone gets hot, without the battery for over a minute. After that, put in the battery, boot up the phone and blow dry the bottom of the phone and heat it up even further while it's booting. I had to repeat the hair dryer heating process many times in order to stabilize my phone because it would reboot within minutes after I try to initially back up with LG Bridge's LG Backup tool. I did manage to overheat the bottom part of the phone so much that Android denied charging the battery via USB connected to the computer. Further exacerbating the problem was that the battery was so hot, LG Bridge denied backup because it thought the battery charge status was under 30% when in fact, my LG V10 showed at 49%. I did get the most important file that I was after on my phone after many tries (kept rebooting on me), but I'll persist to back up the entire phone in case I needed something else before turning this phone over to AT&T warranty service.

Update 1/19/2017: As much as I tried to back up my LG V10 and wipe afterwards, my attempts were futile. The phone couldn't stabilize enough after reaching the home screen, and would reboot shortly thereafter. At least I got what I've wanted. When I kept trying to revive it with the hair dryer trick, it just wouldn't go pass the boot screen most of the time (i.e., LG logo or AT&T logo). It even got to the point where it would turn on slowly (i.e., there's a delay booting up when power was pressed on). So at this point, it appears that the boot loop of death is sinking in further into my LG V10. I also tried the freezer trick again and then going back to the hair dryer trick when the freezer trick stopped working, although not back to back, otherwise that would provide temperature shock to the components. The freezer trick did manage to get further, but it only happened twice where it got to the home screen and then rebooted. Note to those wondering if condensation would trip or activate the moisture sensors on the phone and the battery, it does not when you take careful steps of taking the phone out of the freezer and putting it into the refrigerator and then take it out, letting maybe 10 minutes pass by for each step of temperature transition so that the phone's temperature can get to room temperature without condensation buildup.

Anyways, I decided that I've spent way too much of my time trying to revive my phone to back up data that most likely I wouldn't need. I went the route of sending my phone to LG for repair instead of going to AT&T store and receiving a refurbished LG V10. I'd rather have my phone repaired by LG and receive my phone back with the repaired hardware than to receive someone else's LG V10. I based my decision on this thread here over at Android Central where someone sent in their phone for repair, got theirs back with a clean start (i.e., don't expect LG to either back up your data or reuse your memory storage as no personal data was saved). It is good to note that LG has extended LG V10 warranty of 1 year (12 months) to 15 months. I'm pretty sure LG granted a 3 month warranty extension on LG V10s due to the boot loop issue. I didn't realize I got the extension until thinking back, when I called AT&T warranty center, they told me I had about 86 days of warranty left, which is about 3 months extended from my 1 year of warranty when it ended. The phone was bubble wrapped (removed back cover, battery, SIM, microSD) and shipped off in a small box that I re-used from another item that was shipped to me. Shipping carrier is by FedEx Ground that was paid for by LG, being shipped to LG's repair center in Texas.

Update 01/24/2017: The phone has arrived at the Texas facility yesterday (Monday) according to FedEx, but the status of my repair hasn't been updated anymore than giving me estimated delivery date of 9 days. What's odd is that LG didn't update the received date at repair facility field and have deleted my FedEx tracking number.

Update 01/25/2017: LG updated the repair status last night which pretty much acknowledged item received, diagnosed, repaired, and prepared for shipment back to customer. The repair was "Swap Board (Main/RF) : Others". I should have the phone back on 01/28/2017 and will update then accordingly. It appears that LG probably replaced the entire mother board which would include the 64 GB of memory holding user data, among others. Considering that others have reported of receiving a freshly formatted phone, I would expect the same once the phone reaches back to me. I would highly doubt LG went the extra length to migrate data off of the failing motherboard onto the new one. It would be nice if they did.

Update 01/28/2017: I have received my phone today via FedEx Ground shipping, and they delivered on a Saturday. The status of my phone was factory reset. I can tell it was factory reset because I still have the unlimited tethering (hotspot) enabled from the previous rooting (Lollipop) and then went to Marshmallow and losing the root, but still have unlimited tethering. Also, Android OS is updated to H90021x (from the previous H90021w00), build number MRA58K, with Android security patch level 2016-11-01. You will need to set up the phone just like you did the first time. They also removed my tempered glass and left a narrow sticky film that doesn't cover the entire front screen glass that can be peeled off. Good thing I have an extra tempered glass for the V10. The phone came back with the same serial # and ESN/IMEI that I've sent to LG. If you're like me trying to migrate data from one LG phone to another, it's best to use the LG Backup in Backup & Reset under Settings that's found native in the phone. LG PC Suite and LG Bridge won't work with Verizon's LG G4 (VS986) on Windows 7 for me, no matter what I did (installed many LG G4 drivers, including Verizon's). Some backup apps, such as LG Backup (Sender) and Super Backup & Restore do not back up everything, neither does the native backup LG Backup in the Android Settings menu.

Update 02/03/2017: What appears to be a puzzling action on my repaired LG V10 is that I'm going to take no chance and back up my phone in case I end up losing data again. What happened earlier was that I was surfing the Internet with Chrome, reading up on a news article, when I was prompted to Miracast and enter a PIN. WTF? I ignored it a few times and then it got to the point where my phone was unresponsive with the Miracast prompts, but I was able to force my phone to reboot. Upon reboot, I noticed that the phone loading up was sluggish and not typically responsive. I decided to shutdown my phone to prevent further irreversible problem in the future (hint: boot loop). I waited for my phone to cool down for perhaps a few minutes before I powered on the phone again. This time, when the phone booted up, it was responsive as it normally has. Before all this happened, I didn't use my phone excessively nor extensive in a short period of time. I really have doubts that LG really applied a fix to their faulty connection problem and just used a replacement just to pass by.

Update 02/04/2017: I received an e-mail from LG requesting my feedback with respect to the repair. I gladly answered the survey, gave them good credit with respect to the repair itself, but when it comes to the quality of the LG product, they took a hit and I expressed my concern with respect to the boot loop.