I have a hacked iPhone running (I think) 2.2.1. I have no idea when this started, but I just noticed that I cannot transfer music to or from my iphone. When I open up the phone in iTunes and select the Music section, all of the songs on my phone are greyed out. I am no longer able to drag and drop songs to or from iTunes.

Any idea what is going on or how I might fix it?

Check your iTunes settings and check User Manual, page 59 & 60

That was it! Somehow, "Manually manage music and videos" was unchecked in iTunes. I have no idea how that happened. What's weird is that the same thing was happening on my work PC that has iTunes. I wonder how that got unchecked on both machines.

Oh well, no matter. If it ever happens again, I'll know what to check. I though maybe something had happened on my iPhone that locked the music folder somehow.

Thanks!

You're welcome

I have been able to manually sync my music one song at a time on iTunes until today (July 24, 2010). I'm not sure what made it possible and what now makes it impossible but here are the data points.

August 2008 - Buy iPod Touch (1 gen), have manual song support
July 2009 - Buy iPhone 3GS, restore iPod on it, have no Phone icon but Music and iTunes
July 2009 - Erase iPhone 3GS, do not restore, use Apple's migration to load it, have Phone apps and iPod app, can still manually sync songs
September 2009 - Hack iPhone, still manually sync songs
December 2009 - Unhack iPhone (Apple Firmware), still manually sync songs
June 2010 - Upgrade to iOS 4.0, still manually sync songs
July 2010 - Upgrade to iSO 4.0.1, unknown if manually sync
July 2010 - Uncheck Address Book sync box but reset before pressing "apply", now can definitely not sync individual songs.

My solution was uber simple:

iTunes > iPhone > Music > don't Sync Music
iTunes > iPhone > Movies > don't Sync Movies
iTunes > iPhone > Summary > Manually manage music and videos

I can once again Manually sync one or more tracks by dragging directly to the iPhone without having a copy in my iTunes library (and eating up valuable MacBook hard drive space).

I'm not sure why so many people contend that this level of sync control isn't available on the iPhone like it is on the iPod and iPad lines. Except for the last week, I've always had it and getting it back was a button click on the main iPhone screen.

1.Make sure you have the latest version of iTunes. Please download and install it.
2.Connect your current iPhone to iTunes and sync it. Verify that your original iPhone is backed up.
3.Connect your new iPhone to iTunes (on the same computer you used to back up your current iPhone).
4.iTunes will ask you if you want to restore from a backup or set up your new iPhone as a new phone.
There is also solution about transferring music from iPhone 3G to iTunes on pc, that will work for backup iPhone contact to computer well.
Hope that can help you.