Step 8. Once your phone reboots into bootloader mode, double-check that you can still see “LGE Mobile ADB Interface” in Device Manager. If for some reason you don’t see it, reinstall the driver, see my video tutorial on how to do this.
Step 9. Next type:
fastboot oem unlock
THIS WILL ERASE EVERYTHING ON YOUR PHONE!!! IF YOU HAVE IMPORTANT STUFF YOU NEED TO SAVE SUCH AS BABY PHOTOS, STOP RIGHT NOW AND BACK UP ALL YOUR PHOTOS BEFORE TRYING THIS!!!
Step 10. Pull the battery and put it back in.
Step 11. WHILE holding down Volume Up button, connect your USB cable to the phone. It will boot into firmware update mode.
Step 12. Run the LG Up program you installed earlier.
Step 13. Choose the “…” and choose the TOT file you unzipped earlier and press “Start”.
Step 14. When done, your phone will come back to the Welcome screen.
Step 15. Pull the battery again and put it back it. Then hold down Volume Down and Power buttons together until you see the LG logo. IMMEDIATELY let go of the Power button briefly and hold it down again.
This should get into the following menu, choose “Yes” and hit the Power button to continue.
Then choose “Yes” and hit Power button to enter TWRP recovery.
Step 16. Once in TWRP recovery, tap on “Keep Read Only”.
Step 17. Tap of “Wipe”.