[G2 Q&A, Help & Troubleshooting] fastredponycar:
As the title indicates, I soft-bricked my G2 via bad rom flash (wrong version of CM)

This post will be my outline of how I got my phone out of this mess and operating perfectly.

I foolishly made the mistake of not making a backup so as a result, I have scoured numerous forums and pushed my google-fu to it's limits. Biggest tip I can advise (as if it needs to be said again) is to backup before you do any flashing. If things go south though, here's what happened to me and how I fixed it all.

I rooted and installed TWRP 2.6.3.2 then did full wipe and flashed the wrong G2 version of CM from the internal storage. Rebooted and got the "udc_start()" message of sadness.

Hard reset the device by doing the power button/volume down thing which involves the following:

fully black screen except for tiny little message saying something like UDC_Start() and some other jibberish. Basically it doesn't do anything.

Hold down the power button for about 12~15 seconds. After 10 seconds the phone display will shut off and the LG logo will pop back up. KEEP HOLDING THE POWER BUTTON DOWN.

The screen will shut off again.

Now holding the volume down button, press and hold it and the power button together until the LG logo comes up again.

Release the buttons and then quickly hold down the power button again until you get a device reset screen.

hit the power button to confirm and it will load up TWRP.

I was relieved to be back in recovery but it dawned on me that the wrong version of CM is the only rom I had on my phone. Performing a factory reset does not fix the issue.. just kicks me back to that UDC error.

Next level googling engaged. I had the CORRECT ROM and a couple others for my device downloaded but I had to somehow get them onto the internal storage so that I could flash them.

HOWEVER, I also discovered in the hellfire rom thread, there are issues with TWRP version 2.6.3.2 flashing roms and that flashing the PHILZ recovery from within TWRP (just like flashing a new rom) to replace TWRP would work. I didn't want to take any chances so I got that zip file from here.

http://xdaforums.com/showthread.php?t=2201860

To get these zip files onto the device, ADB push command was the trick.

I grabbed this (if the link is broken, google search for ADB fast boot zip)

http://d-h.st/iqA

And extracted the files to a folder on the desktop.

Next, after reading through some ADB push threads, I copied the zip files into the ADB folder on the desktop and then in windows explorer, hover the mouse over that ADB folder and then shift + right click the folder and in the pop up menu, select "Open command prompt window here"

it's efficiency - not laziness

then with the phone connected via usb cable to the computer, in that prompt type this

adb push ROMNAME.zip /sdcard/

After a short wait, it showed a couple hundred megs worth of a file was transferred. I repeated the command again with the PHILZ recovery zip name and again, it showed completing the transfer.

Time to get to work.

From TWRP, I went to flash a zip, pointed to the PHILZ zip file and successfully flashed that, went back to the main menu and then told it to reboot back into recovery.

I was greeted with the snazzy PHILZ recovery interface.

I then told it to do a wipe for a new ROM install and then after that completed, went to flash a zip, pointed it to the correct version of CM this time and flash was successful.

Crossed my fingers and rebooted the device and SUCCESS! Up and running perfectly.

hopefully this helps those who find themselves in the unfortunate soft brick scenario or something similar that I was in.