I updated to EC05 and am now missing all ringtones and notifcation sounds.
Maybe you need to set them back. They shouldn't be lost.
Only things I had to redo was repopulate my buddies now list, and reselect my notifications & voicecall ringtones. Everything is pretty copacetic- speed test shows upload & download speeds have nearly doubled, 4G connectivity is much better in buildings, GPS is more accurate, battery drain is not as bad, & navigating through the screens & apps is faster than before. I like it!