Install latest Android 4.1.2 Jelly Bean on Galaxy S2 I9100 Download and Extract your Android 4.1.2 firmware. Extract Odin Zip File to Run Odin.exe Turn OFF the Phone Now you will Put S2 in Downloading Mode By Pressing(volume down + alongside Home + Power Button together Run Odin In PC with Administrator Rights Connect Galaxy With PC Odin shows notification "Added" Select The Following File In Odin Click the ‘PDA’ Button, and select the .tar file extracted in Step 1. Click the ‘Phone’ Button, and select file with *modem* in its name (Ignore, if this file does not file exist). Click the ‘CSC’ Button, and select file with *csc* in its name (Ignore, if this file does not file exist). Click the ‘PIT’ Button, and select the .pit file. Use only if you got it while extracting in step 1 above, otherwise ignore it. In Odin window, make sure Auto Reboot and F. Reset Time checkboxes are selected. Please make sure that Re-Partition checkbox is selected, only if y