I GOT TO WORK WOO!! I can confirm that this method does work for the Boost Mobile LG Marquee with OTA Update on ZV4 version. I can give you a more dumb down noob guide because alot of the guides here do leave out certain specific details. Everything you need is on my attachment. The windows enabler, the KDZ updater, and the optional R&D Test Tool (labeled as UpTestEx_Marwin).
Here is a dumb down noob step for those that are new like me to this downgrade. Keep in mind this definitely works with the Boost Mobile LG Marquee phone. I'm not responsible for any brick phones.
Step 1:
Download monsters linked file of LS855ZV9_11.S9_00.P60680.kdz on his first post.
Step 2:
Enable USB Debugging on your phone settings and make sure its set on Charge Only. After that turn off your phone completely and leave it unplugged from computer. (option: if you have not installed the drivers yet, unplug your battery and grab your S/N from the battery compartment of your phone and write it down you will need it for driver installation. After that put your battery back in and leave your phone aside for now.)
Step 3:
Download my attachment (option: if you have already installed the LG Drivers skip step 4 otherwise go to step 4)
Step 4:
Unzip files anywhere. The only folder you should be looking at is the KDZ_FW_UP_EN and you will see a program in there called B2CAppSetup.exe run it should pop up a LG Software Installer and install the drivers from it by looking up the phone manually by going to "Customer Support" and select "Application, Manual & USB driver download". Once in there check mark the Select Model and then search for LGLS855 and type in your S/N below it. It will load up a manual.pdf and the actual drivers. Install your drivers.
Step 5:
Run windows enabler (note: If Windows 7 or Vista run as administrator)
Step 6:
Run KDZ Updater or R&D Tool and select the CDMA SmartPhone and leave it as DIAG (note: If Windows 7 or Vista run either 2 programs as administrator)
Step 7:
Browse to where you downloaded the KDZ File and load into the KDZ Updater or R&D Tool
Step 8:
Now plug your phone into your computer and the computer will load the drivers while it is off. Run the KDZ Updater or R&D Tool software upgrade and it will start loading file. As soon as you run it go ahead and turn on the phone. After your phone boots up and after the boot logo it should next show the S/W Upgrade on your phone. After that leave it alone for about 10 minutes. (NOTE: Very important to understand here. I have not confirmed this with Sprints LG Marquee, but the Boost Mobile LG Marquee only gives a 5 second window for the S/W Upgrade to occur and it is only during boot up. After that the window closes and you will have to reboot the phone to reopen that 5 second window.)
Step 9:
When the S/W Upgrade is finished you will see your phone reboot. Those of Boost Mobile LG Marquee, you will no longer see the Boost Mobile logo on boot up but the Sprint Logo on boot up. After that your phone will boot up with software and you are ready to go for rooting. However those of with continuous reboots goto step 9b
Step 9b:
If your phone is on a continous loop of rebooting and will not boot up correctly power off your phone. Then press the Vol down + Power key and it should boot up the Sprint Recovery menu. Use Vol Up and Down to navigate and press the menu key to select a choice. Wipe out cache and do a factory reset on your phone. Takes about 1 minute but after factory reset is done go ahead and reboot your phone. When the phone reboots you can setup the usual stuff (google sync, email setup, etc.). Your good to go rooting now.
SIDE NOTE: Very important to know for Windows 7 or Vista users. If you do not have windows enabler running it will crash the computer and cause your computer to reboot during S/W Upgrade. Once that happens your phone is stuck in S/W Upgrade mode and the only way to get it out of it is to unplug the battery and plug battery back in. Careful may brick your phone because that happened on my first try at this.
Well I hope that is a bit of a more detailed Guide than previous guide. And I already go my phone rooted too with the stickee thread here as well. I give thanks to Monster and all those that provided me the links (ahem XDA) for the files. Enjoy!
