Samsung I9300 shows emergency call only on your network bar. It can solve with Z3X box easily.
- Run Z3X pro tool latest version and select I9300 model.
- Backup all data of your phone from backup option.
- Then select repair option. You need to root your phone.
- Then click on patch certificate.
Wait few seconds until its done. Now it’s done and solved your network issue.
- Go to setting>built number>tap 7 times
- Com back menu choose Developer option>USB debugging on
- Open King-Root (you can root another method) connect mobile and click on root option.
This method also tested in I9082/I9060 and it solved network issue. This method not solve your problem it can be hardware problem. You can check your hardware.