Sa pagchange ng CSC or (Country Sales Code), pwede kasi madebrand sa ibang carrier ng phone.
From example:
GLB to XTC
XTC to SMA
XEO to XXV (European)
But sometimes, changing csc does not unlock your phone always. Whether kung saan siya nakalocate doon lang siya pwede maunlocked. Parang Region Lock. Kaya Samkey and other code reader comes in.
Hindi lahat ng changing csc does unlock your phone. Except kapag nandito lang sa South East Asian ng region.