Download the rom you want to flash. (cwm flashable roms)
Go to recovery using press and hold volup + menu/homekey + power button
Select update zip from sd card
Select superuserbusyboxinstaller.zip and flash it
Reboot
After boot in app list there will be supersu app , open it and update binary
Now your phone is rooted. (take all back up now using Titanium Backup pro or similar apps )
Now install Mobile Odin Pro
In mobile Odin select kernel, and browse the kernel file u downloaded. Now tap on flash firmware option.
Your phone will reboot and will be having new kernel
Go to recovery mod again using volup + menu/homekey + power button
Now select install zip from sd card select the downloaded jellybean boot loader file.zip
Reboot recovery in advance menu, now phone will reboot and come to cwm recovery
Select wipe data / factory reset and wipe it.
Go to advanced and wipe dalvik cache
Come back to main recovery screen and select Mount and Storage > format ‘’/system’’ and format ‘’/data’’ and format ‘’/Preload’’
Come back to main recovery screen and select wipe cache partition
Now select install zip from sd card select the downloaded romfile.zip
After finishing install it will reboot, if not rebooting automatically then select reboot system in main screen.
Wait for some time, it will take 3-7 mins for the rom to boot normally for first time, keep it idle for 5 mins after booting, then finish initial setup and install apps and other things u needed
