My iPhone 3gs "isn't eligible" when updating to 4.3.4 I get this error message in iTunes when trying to update my iPhone 3GS (non jailbroken) from 4.3.3 to 4.3.4:



Why is this? The iPhone 3GS is listed under “products affected” on the iOS 4.3.4 release notes.
Apple have now released iOS 4.3.5, so they may have disabled the authentication for 4.3.4, as they do with all legacy versions of iOS.. Try downloading and installing iOS 4.3.5.