[General Topics] palswim:
I purchased an LG Viper LTE (refurbished) from FreedomPop and have spent a bit of time playing with it and determining its capabilities and limitations. I want to have a central repository of knowledge regarding this phone. Some of this may overlap with other devices (LG or other), so I will try to provide links where they make sense. I intend to update this thread as I learn more information.

The phone I received came with LG's LS840ZVK (Android 4.0.4 - ICS) firmware, with a few custom apps that FreedomPop has installed, and a ton of bloatware from both Sprint and LG.

Rooting: (I started with a similar guide and forged my way from there.)

Downgrade your Viper (from version LS840ZVK to LS840ZVI). This will also perform a factory reset.

Root the phone after the downgrade (with the Bin4ry Root tool - If you use Bin4ry v36, use option 3, "New Standard-Root").

Backup root (with Voodoo OTA RootKeeper).

(Connect to WiFi and) Apply the System update (your phone will notify you about this - it has an OTA update for you to install).

Since the OTA update did not wipe (factory reset) your phone, use the Voodoo RootKeeper app to restore your root.

I also updated my Profile/PRL (in "Settings > System Updates"), and I believe this restored my 3G/4G data connection.

For FreedomPop, make sure you install the FreedomPop Messaging app to connect your device to the service.

Bootloader:

Unfortunately, I have not been able to unlock the bootloader. Perhaps, if I downgraded the phone to a pre-ICS firmware, I could do so, but I have not tried that yet.

System trim: (requires root)

I mentioned that the phone came with a bunch of bloatware, which seemed to cause tremendous unnecessary battery drain. With root, I was able to remove many of the junk apps. (Make sure to mount the /system partition as writeable: mount -o remount,rw /system) The list of stock apps I removed:

CameraTestApp.apk

CameraTestApp.odex

LGEmail_Native.apk

LGEmail_Native.odex

LGExchange.apk

LGExchange.odex

MLT.apk (some LG debug app that reports data back to LG and drains battery like crazy)

MLT.odex

PlusOne.apk (Google+)

PlusOne.odex

QuickMemo.apk

QuickMemo.odex

SharedStorageBackup.apk

SharedStorageBackup.odex

Shopper.apk

SmartShare.apk

SmartShare.odex

SprintHiddenMenu.apk (I had thought that your system wouldn't connect to Wifi on boot without this app, but that doesn't appear to be the case.)

SprintHiddenMenu.odex

SprintID.apk

SprintID.odex

SprintMusicPlus.apk

SprintMusicPlus.odex

SprintNASCAR.apk

SprintNASCAR.odex

SprintNBA.apk

SprintNBA.odex

SprintTV.apk

SprintTV.odex

SprintVVM.apk (Visual Voicemail)

SprintVVM.odex

Sprint_Installer.apk

Sprint_Installer.odex

Tag_na.apk

Tag_na.odex

WIFIOffload.apk (Sprint Connections Optimizer - removing this will cause Settings to crash when you navigate to "Settings > More... > Mobile networks > Connection optimizer", so remove only if you can live with that)

WIFIOffload.odex

Zone-Sprint.apk

Zone-Sprint.odex

LG has not only locked their bootloaders on their newer phones, but has also implemented some system check on every boot, so you must

TAKE GREAT CAUTION

when attempting to trim your system. If you remove an app that the software deems system essential, your next boot will result in a "Security Error", past which you cannot boot. To recover from this, you will have to reflash the firmware. (See the "Rooting" section; whenever I have put my system into this "Security Error" state, I have just downgraded my system and started the rooting process all over. In any case, you will lose your data.)

I don't know which app caused it, but removing one of the following apps will result in a "Security Error":

BooksTablet.apk

BooksTablet.odex

Magazines.apk

Magazines.odex

Talk.apk

Talk.odex

Videos.apk

(I remove apps by moving them into a backup-type directory, and then I can restore them by copying the files back to the /system/app directory.)

Minor annoyances: (I would hope eventually to resolve all of these and indicate the solutions in "Tips and Tricks".)

Camera shutter sound: I cannot select a silent setting for the camera shutter sound. I have I identified /system/media/audio/ui/shutter4.ogg as the most annoying of the four tone options, and have tried removing this file, or replacing it with an audio file of silence to no avail. Perhaps the camera app stores the audio within the app itself. I could download another camera app, but I'd rather not.

Polaris Office: I cannot remove it. It appears as a system app, but I cannot find any file that provides this app, either in /system/app or /data/app. I extracted all of my system apps, and ran a search for "polaris", and only LGHome3.apk had any match. Perhaps LGHome3 contains this app as well, which would mean I would have to reverse-engineer the app in order to remove Polaris Office.

Tips and Tricks:

Silencing the startup/shutdown animations: I located the files for the animations and simply removed them, rather than keep them and do something to silence them. The /system/media directory contained both files for the boot (bootanimation.zip) and shutdown (shutdownanimation.zip) animations, and I removed both of these files.