Because randomizers alter map data, saving in Lumiose City (especially near the Prism Tower) can corrupt the save due to taxi and lighting scripts. Use the QR code that disables taxis or the one that moves the save point to the Camera Shop. Look for a notation in the code description that says "Lumiose Patch v2."
: To get the best randomizer settings (like "Similar Strength" wild Pokémon or "Standardized XP curves"), it is recommended to randomize the game yourself using the Universal Pokemon Randomizer ZX . How to setup : pokemon y randomizer qr code better
Leo’s jaw dropped. The QR code hadn't just randomized the wild encounters; it had shattered the game's balance entirely. ⚔️ The Unpredictable Journey Because randomizers alter map data, saving in Lumiose
The crack expanded. The 3DS screen went white. Not the soft white of a loading screen, but the harsh, absolute white of a nuclear flash. The console vibrated so hard it slid off his desk and clattered to the floor. The sound was a continuous, rising tone—like a heart monitor flatlining, but reversed, played backwards. How to setup : Leo’s jaw dropped
If you want a "Randomizer Nuzlocke" experience (where wild encounters and trainer teams are scrambled), you cannot do this via QR codes. You must use the Universal Pokemon Randomizer on a PC and play the resulting file via an emulator or CFW-enabled 3DS. How To Get Any Pokemon with QR Codes (ORAS & XY)