DON'T FLASH CF-ROOT AFTER YOU'VE FLASHED XXLE4 (if you don't wanna have problems with wifi).
THIS IS WHAT I'VE DONE:
FLASHED XXKPE.
FLASHED XXKPQ THEN ROOTED WITH CF-ROOT BY AMIT.
FACTORY RESET *2767*3855#.
INSTALLED MOBILE ODIN.
FLASHED XXLE4 FROM EXTERNAL-SD USING MOBILE ODIN (SELECT ALL THE OPTIONS: "ENABLE EVER ROOT", "INJECT S.U. AND MOBILE ODIN", "WIPE CACHE AND DALVIK").
AFTER INSTALLATION IS COMPLETE JUST REBOOT.
EVERYTHING WORKS PERFECTLY, ROOTED PHONE AND NO MORE WIFI ERROR.