ALL Chaos Emeralds:
Enable the 'Level Select' code and then play songs '04', '01', '02', and '06' in order at the 'Sound Test' menu.
First use the level select cheat.
Next play sound 00 a three times, a new menu will apper to allow you to change things like the player character (Knuckles and Tails can be choosen), item set such as s2 items, s3&k items,s2 random, s3 random, and you can also toggle the air cap and toggle flight.
Level Select and Sound Test:
First start a no save game.
Next when the Sega logo appears tap the letters S-E-G-A in that order.
Now hold two fingers on the screen and wait until the level select/sound test screen appears, than you can take your fingers off the screen.