Search for (updated for 3DS games) or PK3DS . These free, open-source tools will modify your ROM.
Downloading a "Pokémon Y Randomizer ROM" for Android is not a one-click affair. It is a DIY project that combines ROM dumping, PC-based randomization, and 3DS emulation configuration. But for those who succeed, you unlock a version of Kalos that Game Freak never intended—chaotic, hilarious, and brutally difficult. Pokemon Y Randomizer Rom Download Android
Adjust settings for wild Pokémon, starters, trainers, and items. Search for (updated for 3DS games) or PK3DS
A Pokémon Y Randomizer ROM is a modified version of the original Pokémon Y game that has been altered to randomize various elements, such as: Pokemon Y Randomizer Rom Download Android