[LG G Flex 2] br0adband:
Using the img file posted by kevin3688 in post #6 above this is what I did earlier today with my LS996:

- use LG Flash Tool to flash the ZV8 TOT file to the LS996 (instructions are elsewhere if needed - you might (I'm saying you might here) have to do a Board DL mode flash first then reflash using the Upgrade DL mode immediately afterward - if you get stuck in MiniOS wait for it to load, tap the screen one time as requested, wait for the menu to appear then hold Power and tap "Normal" to reboot normally - this happens after the Board DL flash process, if you get stuck with the blue screen and the big red 2 hold Volume Down+Power for 20+ seconds to totally power the device off - 20+ full seconds or it'll just keep looping, after which you do the same thing again: Board DL mode flash again, then immediately flash using Upgrade DL mode)

- after that's done, set up the phone as usual but stop before adding a Google account, etc (skip all that, just get to the home screen)

- copy the rootedsystem.img for ZVB to the internal storage of the device

- power down, reconnect device in bootloader mode (hold Volume Up while plugging in the USB cable)

- open a Command Prompt where you have the LG_Root files

- verify the diagnostic COM port using ports.bat

- use the Send_Command.exe \\.\COM(port number) command to start the mode necessary - it works if you see the # prompt

- while you don't have to do it, type id (and press Enter) and you should see a string of device ID information - if the command doesn't work and you see nothing at all I'd start over again (you can disconnect the LS996, power it down, then put it back in bootloader mode and try again - the only reason the command might not work is a mismatch in COM ports but again you don't have to use the id command at all, it's completely optional)

- use the command which is for the LG G Flex 2 LS996 Sprint model ONLY:

dd if=/data/media/0/rootedsystem.img bs=8192 seek=58368 count=522240 of=/dev/block/mmcblk0

to flash the rootedsystem.img (assuming that's the filename, you may have renamed it differently, I don't know) from the internal storage file you copied over to the system partition. Each of the Flex 2 models has a slightly different dd command so MAKE ABSOLUTELY SURE you're using the one I just posted for the LS996 Sprint Flex 2 - if you use one of the other model's dd lines you could do damage to the partition structure so, again, the command I just posted above is for the LS996 only.

When you execute the command you will see nothing but the flashing cursor in the Command Prompt which is normal, no other activity will be noted, nothing on the LS996 either. After maybe 1-2 minutes or so (sometimes less, sometimes a bit more, depending) the flashing cursor will jump down a line, you'll see the # prompt again, and that's the signal the process has completed - it won't tell you anything else, just the # prompt and the flashing cursor.

Type LEAVE (all caps) and press Enter and you're done, the LS996 will then reboot and you should be good to go after the reboot is complete. It will do the full "Android is upgrading..." thing as all the files are inspected/modded/compiled (because it's ART now) as required during the boot process.

After that's done and the phone is properly booted, you'll probably get the notification from SuperSU within a few minutes that it needs to be upgraded, or you can run SuperSU manually and it'll tell you - do the Normal upgrade method, then reboot when required (immediate reboot, don't do anything else with the device after you've done the SuperSU upgrade). After that reboot, get your Google account set up and hit the Play Market to get the latest version of SuperSU (yes another upgrade) and then you should be complete and ready to go with the rest of the device setup as you see fit.

That's the process I've done 15x or more so far with my Flex 2, it's never had issues, never had problems, never failed, so I can't imagine there will be any issues for anyone else as long as they're following the steps accurately. If you do this right and there's still a problem then it typically means something is probably wrong with the device itself for whatever reason and that's the kind of troubleshooting that can't be done in a forum post, unfortunately.

Good luck...