This is so old it was patched ages ago
This exploit is to do with the Tamper Data add on for firefox in which you can buy secret packs On Fifa 12 Ultimate Team that are cheaper or rarer. the pack i have bought mostly since finding this out is the 35k premium gold pack. Lets get started....
Step 1 - After installing the Tamper add on, log into ultimate team on the web app.
Step 2 - Go to the store and choose any pack as it won't matter. Don't hit buy yet though.
Step 3 - Right click the top of the firefox window so it show the menu bar
Step 4 - Go to Tools > Tamper data.
Step 5 - Click start tamper, and select buy pack, if done correctly a window like this should appear.
[url]
https://imageshack.us...513/tampar.jpg/[/url]
Step 6 - Untick the box and click tamper. A window should come up with a pack id number like this :
[url]
https://imageshack.us...851/packid.jpg/[/url]
Step 7 - Change the code to any of these ID's for packs that are secret. I suggest 411 as it is a gold premium pack for 35k coins.
For this to work please use firefox 5 or higher. Thank you.
Oh and to get the tamper add on go to google on firefox and search tamper data add on and install it from there.