need help to downgrade frm 4.4 to 4.2.2 topic

I want to downgrade my phone from 4.4 to 4.2.2..i tried restoring through nandroid backup, bt a md5 error came, so it was unsuccessful.. I tried flashing custom 4.2.2ROM(Gennxt) through CWM after complete wipe, bt dat too stuck on Samsung Galaxy Grand logo..
Help me out..