I don't know what you mean by "boosting" the phone - sounds like "boot", but that wouldn't recovery anything.
The important question is where was the music? If it was on a removable card then take the card out of the phone, put it in a card reader and run some file recovery software on a computer (if you are using Windows Recuva is widely recommended and free). (Edit: as said above)
If it was on the internal storage (which includes the "emulated sd card") then there's probably nothing you can do - file recovery software won't work over an MTP connection.