This technique should work on any stock firmware.
- First flash CWM recovery.Instructions are given below
- Boot in CWM recovery and connect phone to PC
- Download and extract the RootMe.zip package on your PC
- Run runme.bat on PC while phone is in recovery mode
- Reboot the phone after process is over.
- Download the cwm tar package
- Put phone into download mode and connect to the PC
- Flash the cwm tar package as PDA and wait for phone to reboot
Recovery download link: cwm-trebon.tar.md5
The yellow triangle at boot is of no importance.Deal with it :P
Recovery Mode: volume up+ volume down + home + power
Download Mode: volume down + home + power