[G2 Android Development] roirraW "edor" ehT:
Hi. I don't have that device but:

1. It's common and "normal" that LG Flash Tool 2014 crashes at the end. That's not likely an indicator of any issue. It's usually done flashing around 95% or so, but always wait as long as possible - just know it's not odd.

2. It's also normal they if you don't use the CSE option that the device will bootloop. i.e. The current bootloop isn't necessarily related to the bootloop from before flashing the KDZ.

You didn't mention what KDZ/Android version you're flashing. If you're flashing something older than the Marshmallow it OTA'd to, then the the data *must* be wiped because the system data effectively got upgraded to Marshmallow too.

When upgrading via KDZ instead of downgrading, you can sometimes get away with not using CSE because at least with going from one stock ROM release to the very next one that

was available is similar to taking an OTA and the new release is made to take into account the old system data. Unfortunately sometimes OTAs cause bootloops. It's common enough - not a high percentage of possibility but not unheard of either, on any device by any manufacturer.

For what it's worth, performing a Factory Reset in the stock recovery should be the same as having flashed with the CSE option. Unfortunately that too wipes all data including internal storage but not the MicroSD card.

In this case, even if you were flashing a Marshmallow KDZ it might be expected to bootloop since obviously something didn't go as planned during the OTA process and the data might've become corrupted.

You can try merely Wipe Cache from stock recovery and see if that helps, but if it doesn't, you'll likely just have to explain that there's no way to avoid Factory Reset and losing all internal data.

3. I know it doesn't help now but two things that might come in handy in the future before the possibility that this would happen again:

A. Use one or more Cloud service apps to automatically back up any photo or video taken. All the common cloud apps have this option: Google Drive, Microsoft OneDrive, Dropbox, etc. However, I use the Mega app because Mega gives 50 GB of free storage. I have it configured to upload any new photos and videos whenever I have WiFi on.

B. I don't know about that device but on some LG devices they include LG Backup built into the ROM. You can find it in Settings / Backup & reset / LG Backup.

Before taking any OTA you can use LG Backup to back as much or as little as you want to, and you can store it on your MicroSD card which OTAs shouldn't touch. That said, for the paranoid, every once in a great while taking OTAs, flashing KDZs and TOTs wipe the MicroSD card too.

It shouldn't and isn't supposed to happen, but I first heard about it happening for a few others and then it happened to me just a few months ago when I flashed a KDZ or TOT. So you can eject the card while OTAing or flashing to be safe.

Of course, you can always just manually move things from internal to external storage too if you don't care add much about apps and their data.

Edit: meant to also mention just in case that TOTs have more partitions than KDZs and I've also personally experienced an anomaly that flashing any KDZ didn't help me solve an issue until I flashed a TOT. TOTs are rarer than KDZs, usually at the most you can find one TOT per device, not one for every stock ROM release for the device like KDZs.

In the case of my VK810, an XDA user had to purchase the TOT from a Chinese website but but lo and behold that it worked. TOTs always wipe all internal data/storage though just doing a Factory Reset will probably be all you need - just wanted to tell you in case that knowledge comes in handy.