https://gbatemp.net/threads/pokemon-sacred-gold-storm-silver.327567/

The v1.1 patch that adds the Fairy-type to the game (and also changes the shiny rate to 1/257) can be found at the bottom of this post.
Please note that the Storm Silver version of the Fairy patch has a bug that means the Poké Mart items are not changed to what they should be.