So I was messing around looking for a new one and couldnt seem to find a one that worked, then I was trying some new ways, and found a way that worked.

FOLLOW MY STEP BY STEP GUIDE

1: Sign in on your second Controller
2: Go to store, press "X" twice on your second controller, 1 second after that press "O" on your 1st controller.
3: Once the " Error " sign has came up press X with your 1st controller
4: Sign into your master prestige account
5: Wait 5 seconds before entering Online.
6: Enter online home page.
6.5: Wait 2 seconds, Check to see if you Recieve the "Message of the Day" from Treyarch... If you do not recieve that message you've done it wrong and will have to re-do step 1-4.
7: Check to see if your Account is MASTER PRESTIGE ( If not do again )
8: Press the PSN button on your controll pad, make sure your on your Master Prestige account. If not, you've done it wrong and re-do) If your on your master prestige account. SIGN OUT and Turn Your PS3 off by hitting that " Turn off " button on the console.
9: Turn your PS3 on
10: Sign into the account you want to prestige ( Same account as in step 1-4 )
11: Enter online mode
12: Wait 5 seconds then you'll recieve a message from Treyarch Saying " Error your statistics will be updated " (Only happened to me once out of 3 accounts dw).
13: You've completed the Master Prestige Glitch.


Takes a good few attempts!
Enjoy!