The latest version of Android, Ice Cream Sandwich, has been released only on Galaxy Nexus. This version of Android is certainly the very best version released so far and Android users have been craving to use it on their devices. But the problem that the owners of previous models of Android devices are facing is that the ICS update would not be available for the previous devices before 2012. However, this is what would happen officially and unofficially, you can use MIUI version that has been built upon the ICS framework. To activate this version on your device, you would have to follow a few simple steps. First of all, download Gingerbread XXJVS firmware which would be in the form of a zip file. Extract this zip file in any desired folder and then download Odin3 flash tool which would be extracted in the same folder. Execute the Odin3 v1.7.exe file present in the later download. After that, reboot your device while pressing the volume down + ok buttons. Then connect your device to your computer and open the PDA tab from the Odin3 window and select CODE_I9000XXJVS_CL565837_REV03_user_low_ship.tar from your folder. After that, select GT-I9000-CSC-MULTI-OXAJVS.tar from the CSC tab from the same folder. The flashing process would start once you click the start button in Odin3. After that you would have to restart your device in the recovery mode.
In case you had previously rooted your device, it would be unrooted before this update. To root it again, just download the rooting file and just keep it in the zip format. From the Odin3 flash tool, click the PDA tab and select CF-Root-XX_OXA_JVS-v4.1-CWM3RFS.zip. There isn’t any need to bother about the rest of the tabs. Start the flashing process and once it is complete, the phone would be rebooted automatically. Then you would need to download the MIUI ICS ROM for your device and copy it to the SD card of the phone. There would be a CWM Manager app which you would open and choose the option to reboot to ClockworkMod Recovery. In that mode, you would have to wipe the cache, data as well as partition. Finally, install the MIUI ICS file from your SD card that you had previously saved. Once the process completes, just reboot your device again and that’s it, you would be ready to enjoy the ICS update.