1. Turn Off Your Phone Completely [ Skip This Step If Your Phone Already Off ]
2. Now Press and Hold Volume Down + Home Button and Power Button Togather.
3. In 2-3 Seconds U Will See Warning Screen With 2 Options.
4. Now Press Volume Up Button Once To Continue To Download Mode Screen.
5. Done Now Your Phone In Odin Mode and U Can Now Write Firmware With Odin Tool.
Download Latest Odin Tool Version - Samsung USB Drivers - Instruction To Write Stock Firmware On Samsung Phones With Odin Tool
