How to Duplicate Pokemon on Ruby Version
- 1). Enter the nearest Pokemon center. There is a Pokemon center in most major towns and cities. You may want to use one of your Pokemon's "fly" ability to speed things up.
- 2). Boot up the personal computer (PC) in the Pokecenter lobby. Choose the "Bill's PC" option.
- 3). Deposit the Pokemon that you need to clone, and save your game. Then, move the same Pokemon to a different storage box. A message will appear asking you to save the game. Press "accept."
- 4). Turn off the Game Boy while the game is saving. Make sure that you do this while the game is saving, not before or after.
- 5). Turn the Game Boy back on and check both boxes to see if you have two duplicate Pokemon. If you did the process correctly, you should now have duplicated your Pokemon.
Source...