[LG G Flex 2] smithisize:
I caught the deal on ebay for an inexpensive Flex 2 not so long ago and, of course, the first thing I set out to do was update and root it.

The stock image ran 5.0.1, w/ firmware H950 v10b. I attempted an OTA update several days in a row, being told each time that none was available (the phone is AT&T branded and my service is through AT&T), but eventually grew impatient to get that sweet, sweet 5.1.1 action going.

After attempting to flash the 5.1.1 v11x rooted system image provided by randrew87 (here), I was greeted with a nifty little 'Security Error' boot screen and pursuant loop. Sadly, I wound up flashing the stock system dump I created following that tutorial to get back into a usable state.

Left with no other options (assuming, correctly, that I'm being impatient with OTA), I decided to try the 5.1.1 H950PR v15a firmware.

NOTE: Though I chose to flash the unrooted 5.1.1 H950PR image first, you may not have to complete this step; I'm not sure, but it's possible that you could simply write the rooted image instead.

First, I followed this wonderful tutorial by Sj12345: [KDZ] H950PR 5.1.1 compatible with ATT H950 with Video!!!

My initial plan was to write the unrooted system image and root using any of the available tutorials. Unfortunately, I couldn't get any of the tutorials to work for me as my device simply refused to allow r/w operations to /system while using the COM interface, regardless of my approach.

After a little trial and error, I discovered I could write the rooted H950PR-v15A image, provided here by Sj12345, and achieve root.

Here's how:

Download rootedsystem.img (from Sj12345's post)

Download LG Root Tools.zip (attached) and extract to a folder

Copy to the root of your internal sdcard via means of your choice (I used MTP mode and Explorer to drag and drop)

Power off your device

While holding VOLUME UP, insert a USB cable.

Open a Command Prompt window where you extracted the archive (easiest way is by holding Shift then right clicking within the folder > Open Command Prompt Here)

Double click ports.bat (included in the archive). Find the diagnostics port (in my case, COM4)

Type the following:

Send_Command.exe \\.\COM4

(replacing 4 w/ your com port)

You'll be greeted with a '#' prompt, terminal-style. From there, issue the following command (thanks to randrew87's thread):

dd if=/data/media/0/rootedsystem.img bs=8192 seek=53248 count=534528 of=/dev/block/mmcblk0

The operation will take a couple of minutes. Once complete, you'll again be greeted with the '#' prompt.

Type LEAVE (all capitals), and hit enter. Your phone will reboot and have a clean, rooted image installed.

Profit.

This guide is obviously very specific, requiring H950v10b 5.0.1 firmware on an AT&T flex 2, no OTA availability, and a myriad of other issues (such as /system being readonly). My hope is that this will aid others who don't fall exactly into the parameters described in existing tutorials.

Thanks again to randrew87 and Sj12345 for their great posts and work; this thread is merely a slightly different approach to their pre-existing methods. They did the work, not me!

Hope this helps someone!

Regards

Smith