[jbenantim]

Hi friends,
I have tried in vain to set an optional ringtone on my lumia 520 any help and how to update my OS to windows 8.1

[N_LaRUE]

For the ringtone you need to set the genre of the MP3 to Ringtone and place it in the Ringtones folder of your phone. Attaching to a PC is the easiest way to do this.

For your phone, if you don't have a phone that is currently receiving the WP8.1 update you can use the DP.

To check for your phone go here: Software update for Nokia Lumia with Windows Phone 8 - Nokia

For the DP read this: Windows Phone 8.1 Preview for Developers is now live | Windows Phone Central

[switch side method]

Download ringtone maker....so much easier and if you want to add album art then download MPAtool