While Apple remains mum over the error code issues caused with the new iOS 4.2.1 — Snazz and Scott Hobbs have the solution to fix it up. On another note, it looks like the iOS 4.2 ignites yet another problem, this time for the iPhone 4 and iPhone 3GS users.
Folks at Apple discussion forum have posted this issue and also have come up with the solution. The issue is, after installing iOS 4.2.1 on iPhone device, the iPod app is empty. That is, there’s no music library when you tap on the iPod icon on your iPhone.
If you were exposed to this iPod app problem, then fret not because the solution is fairly simple. Taking a back-up is not necessary here, but do it anyway.
Fix iOS 4.2.1 iPod App Problem on iPhone
The solution is to play the song on your iPhone via iTunes. That is, connect your iPhone and launch the iTunes media player.
Now, from the left panel, choose iPhone –> Music and hit the play button on your iTunes. The iPhone device will lit up with the ‘sync’ message. That’s it! All the media files can now be accessible from your iPhone.