Incearca sa intri in recovery mode si dai factory reset https://www.youtube.com/watch?v=nOntRTi8qvE
Daca nu merge nici asa incearca sa-l resoftezi http://www.androidrootz.com/2014/07/how-to-unroot-lg-g3-all-variants.html
Sper ca te-am ajutat
Daca iti intra in download mode poti reinstala softul. Ai explicat totul aici: http://forum.xda-developers.com/showthread.php?t=2432476