REPAIR INSTRUCTIONS:
   USB cable:
  1. Phone must be powered on.
  2. Type ##634#, then type *#7284# and choose 'QC RmNetComposite' option.
  3. Apply confirmation and wait till phone reboot.
  4. Connect USB cable, install drivers if needed.
  5. Select diagnostic port in port settings.
  6. Fill values, what you need to repair.
  7. Press 'Repair' button.

Operation: Repair
Selected model: GT-I8750
Selected port: COM64 Qualcomm HS-USB Diagnostics 9001
Software version: 45.9

Reading phone info...
Reading IMEI... OK
IMEI: 0
Reseting IMEI... OK
Rebooting phone... OK
Reading phone info...
Repairing IMEI... OK
Reseting... OK
Repair done

Done with Samsung Tool PRO v.45.9 [GT-I8750,Repair]