How can I update Samsung Galaxy SII SHW-250K from ICS (4.0.4) to jelly bean? I tried using samsung kies but it shows that "SHW-250K does not support initialising".
You can simply flash win Odin GT-I9100 firmware. Firmwares you can get from sammobile
Odin you can get from http://web.djodjo.org/?a=download:android:tools:win:bootloadertools
You can also check this tutorial for flashing with Odin.