I can verify that after some trial and error I finally was able to manually push a PRL to the Marquee using this method.
1) Get your MSL. As far as I know, the only way to get your MSL with the Marquee is to call boost. You should be able to get it easily by telling them you want to do a factory reset.
2) Install all three LG driver packages. Go here:
LG LGLS855 Support: Find Manuals & Warranty Info | LG USA
Download the LG Mobile support tool found in the middle of the page.
3) Install the software, tell it you want to download drivers for the LS 855. It goes through an awkward install process that should download 3 driver packages.
4) After the drivers are installed, put your phone into DM by dialing Dial ##7678#, entering your MSL, and checking the box that says DM mode. DO NOT REBOOT.
5) Now when you plug your phone into your PC, it should install a bunch of drivers including one for a virtual COM port.
6) Put your phone in USB Debug Mode: Settings -> Applications -> development -> USB Debugging
7) Find a PRL file you want to use. You can find a bunch of them here:
8) Now you are ready to use CMDA Workshop. Follow the instructions here starting at "1. Open CDMA-Workshop:"
Idiot's Guide: Flashing PRLs on the Precedent
Substitute LG xxx whatever for Samsung xxx whatever in the steps, and skip step "2. goto your Phones DialPad and dial ##8778# -> enter your MSL -> Select USB:"
If you are using MarkyBeats, you should be able to flash PRL without switching to DM.
Also, you might want to try DFS instead of CDMA workshop. My trial ran out and I couldn't find a workaround, but I was able to flash a new PRL using this guide:
[Guide]How to change your MSL and PRL (Not CDMA Workshop)
Using DFS, connect to modem first, then serial port, then proceed as instructed.
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