This device is not eligible while updating iPad

When I tried to update my iPad from iOS 4.2.1 to 4.3.3, the iTunes kept getting an error message: "this device is not eligible" on my Mac. The iPad was stuck in DFU mode with black screen.If you have the same problem that keep having trouble to update to 4.3.2 to 4.33, try the following steps.* In Finder to to Go > Go To Folder, and type in /etc.* Open “hosts” file in TextEdit.* Then edit the