Enter into download mode by turning off your phone, then hold vol + and plug it to your computer.
Download the official firmware for your device.
unzip FlashTool.1.0.54, open the folder and launch UpTestEX.exe
Phone mode: DIAG
Select kdz file: browse for your official firmware
Then click: normal web upgrade test
Then click: Upgrade start
a new window will show, chose english language. Country: korea, then click ok and wait untill the firmware installs.