If you can find the KDZ firmware file, you can flash your lg g2 yourself using LG Flashtool 2014.
As long as it is Official Firmware (not a custom Rom) you wont need to root your phone.
Do your research first and make sure you understand what you are about to do and the possible consequences...
Google will help you find all the information you need... :smileywink:
TSD.:smileyhappy:
