Lg l7 2 (p710) kdz problem topic

Hello,
First sry for my english...
So my problem is I was watching youtube video how some guy rooted and installed cm mod on lg l7..he said that we should install some new kdz..I did that using R&D test tool and after that my phone has only white strips on his screen..I tryd to install back old kdz but I dont know which 1 to install, does any1 have some suggestions?
I'm pretty much noob in here so any help would be appreciated