does your phone show white screen by turning on?

Flash it with a standard DCU-60 Cable, you need't to pay for flashing, there are free flashers like XS++ which can flash your phone.

Or when your GDFS is demaged you can flash the GDFS through Setool2 lite.
But first make a Full flah as a member here sais. It means flash 2files(Mein+FS) and than again the Main