Never played zelda, so it's all a common practice.
Game has a ram address with music id, probably it is the same address as sound id, which will make it easier to find by performing some ingame actions with different sounds.
To shut down music game writes 00 to sound address, and a bit later writes music id byte to play another one. Usually something like this
So either prevent it from writting 00, and also from writting menu sound id, or change menu id to title id.