Here we go: (assuming you use 2x2 LttP big chest tiles).
1. Set up your combos. Make the left bottom one have the top two unwalkable. Make this combo be a Boss Lock Block with the same combo next to it, but with only the left top corner non walkable. Make that a trigger perm combo.
2. Now, with the combo that should appear that it is horizontally flipped, assign the Boss Lock Block 2 combo. Make the combo next to that be the same as the one before it, but it should have only the top right walkable, and be a trigger perm combo type.
3. Set the top of the chest (the part that opens) as an overhead combo that is unwalkable. This should make it so you cannot see the item that you will place. Do the same thing for the other combo that appears flipped. Now, set the secrets in that room to make the closed chest appear open.
The effect of this will be as follows:
Link will walk up to the chest, which is a Boss Lock Block combo. If he has the Boss key, the Boss Lock Block changes and makes a little spot of unwalkability. Thus, the Boss Lock Block 2 does the same, making enough for link to walk through. Once Link moves, the trigger perm that is set to those combos will take away the overhead combos covering the item, and make 2 slightly walkable open chest tiles, allowing Link to walk up and grab the item.
EDIT: Either this is a ZC bug, or it is intentional, but you have to put secret combos over the lock blocks you use to open the chest, because if they are boss lock blocks then they come back when you leave the screen....
Enjoy doing big chest with no warps.
![icon_wink.gif](style_emoticons/default/icon_wink.gif)
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EDIT 2: When you try this, since boss keys don't open boss lock blocks in 182, be sure to use the magic key. Also, if you want the secret combos to stay, you have to use level 0. Just be aware that it might not be working because of these bugs, but I did get it working.
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