First start a new game. Then after you have selected a starter pokemon, work your way through the game, not saving at all, until you can catch pokemon. Catch any other pokemon then deposit your starter into the PC box. After that, change boxes and when it asks you to save click "yes". When it starts saving reset(or turn off) the game. When you go on your main file the starter should be in the box that it was placed in. Make sure before you do this glitch to go on your main file and move the number one pokemon in the box, as the starter will replace it. Use this glitch at your own risk, it can mess up game data.