Here's a safe and easy way to unbrick your LG Optimus V. Worked like a charm for me.
First, what happened with me was, I was using Xionia recovery and was wiping in preparation of installing another ROM. Under advance, for curiosity sake I hit "LG Style Wipe", which, from what I understand is just like hitting Factory Reset within the phone in the menu settings. My phone would boot to the screen saying "factory reset...formatting data...formatting cache...do not remove batttery...rebooting", then would sit at the pink LG logo screen. Could not boot into custom recovery at all, no matter what. Could only boot into Emergency Mode.
I wracked my brain trying to use KDZ, KP500 with LG Utility, while in Emergency Recovery to no avail. So finally, here's what I did:
What you'll need is: ROMTools, stock ROM (I made a nandroid backup before I originally rooted), a basic clockwork recovery, and ADB installed on computer.
1) place the recovery in your ADB tools folder
2) prepare a command window: on computer -> Run -> cmd, then start ADB by typing (without the quotes) "cd C:\Program Files\Android\android-sdk-windows\tools" then hit enter (or where ever you installed ADB at)
3) Type (without quotes) "adb reboot bootloader", do not hit enter yet.
4) Now, here's the tricky part. Plug phone in to computer. As the phone goes through the Formatting, blah, blah, blah, go back to ADB and hit enter. This may take a few tries. It may say "device offline" or "no device detected". Just keep trying. This is actually the hardest part.
5) Once your phone reboots into bootloader (blue screen), go back to ADB and type (without quotes) "fastboot boot "recovery-RA-GNM-thunderc-s-1.1.0.img" (or whatever recovery you placed in your ADB tools folder in step 1)...If it fails, just try again. It took me a couple tries.
6) Your phone then should reboot into clockwork recovery. You should now be able to mount your phone as "USB mass storage device" under "mounts and storage". If computer does not connect try unplugging and plugging back into computer. If it still doesn't connect, you may need to reinstall LG drivers, which you can do using ROMTools under flash a recovery. but, ONLY install the drivers which it will do first (3 drivers). after drivers install, exit out.
7) Once you mount your phone to computer, put the stock ROM on your SD card.
8) Choose "install zip from sd card" then choose the stock ROM. Unless you have a nandroid backup of stock ROM. In that case choose "backup and restore", then choose the stock nandroid backup. Once it installs, reboot.
9) The phone will still go through the "Factory reset, formatting, blah, blah, blah" screen, but after it reboots, but it will boot into the stock ROM.
10) Now to get rid of that annoying "Factory reset" boot screen. Once your phone fully boots up, open ROMTools. Type 2 (Flash recovery to phone), then 1 (LG Optimus V), then 1 (install drivers, obtain root, flash recovery), but ONLY install drivers (3 of them) then exit out. If you did this in step 6), you shoot be able to skip this step.
11) Open ROMTools folder and click "one.exe" (SuperOneClick) Once it opens click on "UnRoot". This will unroot your phone. After it goes through everything it may say fail at the end because it can't find the busybox folder. No worries, it should be unrooted. I then downloaded Root Checker (free on the market) just to make sure it worked. Exit out when it finishes.
12) Reboot phone...It should now reboot with now problems, just like new.
13) Now you can re-root, flash your custom recovery, then install your ROM of choice.
This whole process takes only about 15-30 minutes.