If you encounter problems during flashing, upgrading or downgrading you may fall victim to your MEID/ESN being zeroed out. The usual cause is pulling your battery while stuck on the white LG Software Update screen.
How do I know my MEID is zeroed out?
If you happen to be using LGNPST, it's fairly obvious from the info on the right hand side. If you're just using your phone, from the Home screen click: Menu -> Settings -> About phone -> Status and look for the following:
MEID HEX: A0000000000000
or some variant
Congratulations! You're zeroed out!
How do I repair it myself?
This is the way I did it, and it was fast and easy..
This is assuming you already have all your drivers in place
Google and download the newest demo version of DFS CDMA TOOLS ,download it and install it.
Pay for it or whatever you need to do
1. Connect your phone in debug mode.
2. Run DFS
3. Connect to your port phone through its debug port.
4. Now click the play spc button, to send the spc of 000000 or put whatever your spc is in that box and hit send. You will see device unlocked.
5. Now in the programming tab, then general tab, under the lock codes section, click on reset, then click write to clear all codes, then under the MEID section, click read. You will see all zeroes here.
6. Now type in your MEID hex, dec, and pESN as needed, then click write. Also Type in your IMEI at the bottom if you have one and click write. These are located under the battery or on your factory box. You will see that the the software automatically converts your meid to (p)esn and meid dec and fills these boxes automatically.
7. After this completes successfully. Your MEID has now been repaired.
8. Click Reset at the top and your phone will Restart. You should now boot back up with service restored and your MEID back in place.
This should be stickied because A LOT of people have had this issue and it took me 10 hours of searching to figure out this solution. There are other solutions that take A LOT more effort and work/using adb and more... but this one I figured out on my own... this is straightforward and easy.