Crest Roundup
You can find extra Crests when you've completed Harry Potter's adventure. At some places in Hogwarts you can find firework boxes. If you burn these with Incendio,they will explode and a broken Crest will pop out. Repair it with Reparo and pick it up. (For instance, check out the box nearby the duel club of Hufflepuf)

Hogwarts Crest Rewards
Description: Collecting the Crests hidden around Hogwarts unlocks the following rewards:

3 Crests	Two Player Dueling Pack 1: Draco & Luna
8 Crests	More health in duels
14 Crests	Two Player Dueling Pack 2: Training Ground Dueling Arena
21 Crests	Dungbombs in prank boxes around Hogwarts
29 Crests	Two Player Dueling Pack 2: Crabbe & Goyle
38 Crests	Score boost in flying events
48 Crests	Exploding Cauldrons in prank boxes around Hogwarts
59 Crests	Two Player Dueling Pack 4: The Transfiguration Dueling Arena
71 Crests	Max health in duels
84 Crests	Two Player Dueling Pack 5: Ginny & Hermione
98 Crests	Love Potion in Potions Club
113 Crests	Two Player Dueling Pack 4: Paved Courtyard Dueling Arena
129 Crests	More mini-crests with each cast
150 Crests	Dueling Two Pack: Snape

Locked Gates
How to: When you see the shields behind the locked gates, use Wingardium Leviosa and hit it into a wall to break it. Lift the pieces out through the gate and repair the pieces to get a shield.

Castle Gates
How to unlock: To unlock the Castle Gates multiplayer dueling area, enter this code at the Rewards Menu:

RIGHT, RIGHT, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, LEFT, RIGHT, START

PS2 Cheats for Harry Potter and the Half-Blood Prince

Harry Potter and the Half-Blood Prince cheat codes

Harry Potter and the Half-Blood Prince cheats