The last Minecraft Patches on the Xbox 360 seems to have fixed some of the duplication exploits, which honestly I’m not sure why they bother since the PC version has Creative Mode which allows full access to any resource or block in the game.
The patches really only made it a bit tougher to duplicate items however. Most of the glitches had to do with someone placing an item into a container of some kind at just the right time, while another person broke it. It was easier at first because holding down the A button placed and then picked up the item rapidly, but that’s no longer the case.
It’s still possible to duplicate items, but you just have to have quick fingers now.
1. You either need a friend in your world, or a second controller. Having a friend will be quite a bit easier.
2. Place a chest on the ground, and place a single item or brick of what you want to duplicate into the center square of the chest. I’m not sure if needs to be in the center or not, but that’s what worked for me.
3. The person with the quick fingers needs to stand on top of the chest, open it up, and start pressing A repeatedly as fast as possible on the item in the chest that you’re trying to duplicate.
4. The second person needs to begin breaking the chest with their hands until it successfully breaks.
5. If it worked, you should see a copy pop into your inventory, and a copy on the ground that’s glitched and can’t be picked up. If it didn’t work, then try again, because it seems to depend on clicking A at just the right time when the chest breaks.
6. If you have your duplicated copy, you’ll notice that you can click X repeatedly to keep dropping copies of that item indefinitely. Clicking A will sometimes drop a stack of 64 of the item, however you’ll notice quickly that these are extremely glitched and seem to disappear often, and don’t seem to really work for anything.
I suggest using whatever you duplicated as quickly as possible. A good idea for example is to not duplicate a diamond tool, instead duplicate a piece of diamond, then make a ton of tools and swords out of your duplicated pieces so you have legitimate crafted tools that won’t glitch.
Also, this trick doesn’t seem to work if you already have duplicated items in your inventory.