How To Flash LG Optimus One Back To Original Firmware

1. Download and install driver for LG P500
2. Restart your computer, then go to Device Manager and disable LGE Virtual Modem
3. Download and extract kdzupdater and install msxml.msi
4. Download LG P500 firmware that is suitable with your region.
5. Turn off your phone
6. Press and hold Power + Volume[+] + Back buttons, until your phone boot to emergency mode
7. Connect your phone to PC via USB
8. Run KDZ_FW_UPD.exe in administrator mode
9. Select Type: 3GQCT and select PhoneMode: DIAG
10. For KDZ files, select the firmware that you have downloaded
11. Click launch to start the update
12. Wait until it is done (around 5-10 minutes) and unplug the USB cable
13. Do a hard reset, hold Power + Volume[-] + Home buttons
14. Done!

*Do it at your own risk