Hi guys, forgive me for not giving proper introduction.

I have the same problem before updating to jb 4.2.. what I did just clear out some phone memory/storage about 1gb.. before this my memory is not enough to download that update. My bad bcoz i dint check it before... So clear up some memory first. And then try download the update again..
It will tell you the download is corrupted.. dont worry.. proceed the process until the red acclmtion mark.. leave it right there..
Your must have sufficient battery for this process..

Then after a while.. the red mark dissapear and then boot again.
Go to update once more and download the update again.
Dont interrupt the update with gaming or anything..
It work for me.. just want to share after figure it out the whole day..