title: useing libimobiledevice to set iphone's ringtones
body: <p>I am using libimobiledevice to write a program named iRingtone. Hoping to set ringtones without iTunes. </p>
  
  <p>Steps:</p>
  
  <ol>
  <li>uploading .m4r  to /iTunes_Control/Ringtones/</li>
  <li>update plist file /iTunes_Control/iTunes/Ringtones.plist</li>
  </ol>
  
  <p>The ringtone can be preview under Settings->Sounds->Ringtone, but it CAN NOT be set as the ringtone. <strong>*<em>The system force it fallback to the default ringtone -- Opening(Default).</em>*</strong> 
  Every time when i use iTools to set the ringtones, i can find that the size of <strong>MediaLibrary.sqlitedb-wal</strong> and <strong>iTunesCDB</strong> under /iTunes_Control/iTunes/ changed. But they are <em>binaries</em>.
  So, does any one know the <strong>correct format</strong> of these two files. 
  Or, These two files have nothing to do with ringtones, then how to correctly set the ringtones?</p>
  
  <p><strong>Thanks a lot.</strong></p>