iPhone 4 failed to update to 4.2.1

[ZionX]

i tried to update to 4.2.1 firmware. it failed now i dont know what to do. its suck on recovery loop after reinstalling the update and trying to jailbreak it and see if it activates it. someone please help me..

[iYeow]

If you are restoring to stock firmware , use restore in itunes to restore from recovery mode.
If you have TU, open it , go to advance and uncheck the box : set hosts file to Cydia upon exit.