I've started Oracle of Seasons and have beaten it and have now started a Linked game of Oracle of Ages. i am up to the 4th dungeon in it.

Question: how do i get the level 3 sword (master sword)?

Problem: the FAQ i refer to says to speak to a Zora in the Heroes Cave (for a secret) in Oracle of Seasons. the problem is that the heroes cave does not change to the hard mini dungeon (which i think the zora resides in) once you beat the game (non-linked).

how do i get the master sword? must i beat Oracle of Seasons -> Linked Oracle of Ages -> Linked Oracle of Seasons ? if yes then thats retarded, why would i want the sword? why would i repeat a quest i already did? how would i face gannon if zelda is locked in the tower in Oracle of Ages?