Any data that was on the device but not in iTunes or saved in a backup is gone at this point.
Error 1479: This error occurs when trying to contact Apple for an update or restore. Quit iTunes, disconnect from USB, restart the iOS device, reconnect the device to the computer, then launch iTunes and attempt to update or restore again.
Error 1639: See this article for resolution.
Errors 3000-3999 (3004, 3013, 3014, 3018, 3164, 3194, and so on): Error codes in the 3000 range generally mean that iTunes cannot contact the update server (gs.apple.com) on ports 80 or 443.
- Update to the latest version of iTunes.
- Verify the computer's date and time are accurate.
- Check that your security or firewall software is not interfering with ports 80 or 443, or with the server gs.apple.com.
- Follow Troubleshooting security software. Often, uninstalling third-party security software will resolve these errors.
- An entry in your hosts file may be redirecting requests to gs.apple.com (see "Unable to contact the iOS software update server gs.apple.com" above).
- Internet proxy settings can cause this issue. If you are using a proxy, try without using one.
- Test restoring while connected to a known-good network.
Error 3002: If you experience this error while updating an iPod touch (2nd generation) or iPhone 3G, please use the standard update or restore process in iTunes (click Update or Restore).
Error 3014 may indicate that you need to free up more disk space on the computer before trying to restore again.