Requirement

Samsung Latest Usb driver http://androidxda.com/download-samsung-usb-drivers

Nv item reader_write https://drive.google.com/file/d/0B6Rh2XPre9rOakxQcHo5T015dXM/view

After you follow the step above enable usb debugging on your device by going to setting>build tap it 5 times then u will see a pop up with the message you are now a developer

Change to change USB mode by dialing *#0808# or *#7284# with phone connected to PC select Qualcomm usb settings and then check RMNET + DM +MODEM click on wait for window to install the driver, confirm installation by right clicking computer icon then scroll down to select properties, on the left hand side select device manager then u will see the COM port installed

Unzip Nv item reader_writer and run as administrator then click connect from the top menu wait till you get a message with connect to COM port successuful

read more http://mobileinfosite.org/repair-samsung-loscorrupt-imei/