RBY: The Real Way to "Duplicate" Items
Posted by: echinodermata
Date: 2008-07-30 21:30:58
Summary: A pile of x255 of an item duplicates itself when an item above it is tossed.
Here, "duplicate" means that an extra pile of the item appears. It does not mean increasing the quantity of an item (as with encountering Missingno., 'M, .4, A, etc.).
All this was done on a cartridge Blue version.
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Obtain x255 of an item in a single inventory space ("pile") by any means. I used the Old Man Glitch. In this example, we have 255 Master Balls.
The glitch occurs when an item above the x255 pile is tossed (or deposited, sold, or used). There will be two adjacent piles of Master Ball x255 where there used to be one.
There must be exactly x255 Master Balls to trigger the glitch.
Tossing an item below the Master Ball x255 pile causes no glitch.
Swapping the places of two items causes no glitch.
When there are two or more non-adjacent item piles of quantity x255, only the x255 pile closest after the tossed item duplicates.
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For example:
Escape Rope x1
Master Ball x255
Ultra Ball x255
Rare Candy x129
Great Ball x255
Cancel
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Using the glitch once will make the last item in your inventory act as the Cancel button. Twice will make the second to last item in your inventory act as the Cancel button. And so on.
You cannot scroll beyond the Cancel button, even though the scroll arrow is there.
Items below the acting Cancel button will be unreachable.
The acting Cancel button can be swapped with another item, which will act as the Cancel button.
Buying an item (or otherwise adding an item to your inventory) will erase the item acting as the Cancel button as well as those underneath it (not like you could reach those anyway). A normally functioning Cancel button will be directly below the bought item.
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Continuing with the above example, Escape Rope x1 was tossed, resulting in this:
Master Ball x255
Master Ball x255
Ultra Ball x255
Ultra Ball x255
Rare Candy x129 (acting as cancel button)
Great Ball x255 (unreachable)
Cancel (cannot be seen)
Buying a Parlyz Heal will result in this:
Master Ball x255
Master Ball x255
Ultra Ball x255
Ultra Ball x255
Parlyz Heal x1
Cancel
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Aside from the Cancel button issue, all items will function normally.
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My explanation of this glitch is as follows:
When an item is tossed, each item below it is copied upward one space, starting with the item directly below the tossed item and going down. However, when the game encounters a pile of quantity x255 while going down the list, it is copied up, but the items after it are not, leaving two adjacent piles of x255 of the same item. The game still decreases its count of the total number of inventory items by one (which accounts for the messed up Cancel button).
I think when the game goes down the list on this copying spree, encountering an FF byte signals "Cancel button! Stop copying after this!" even though in this case the FF byte is for item quantity, not item type. Under normal cases, nobody would have x255 of an item anyway. Under normal cases, since the Cancel button masks anything after it (I think), the game doesn't have to delete the extra Cancel button left behind after copying the cancel button up one space.
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Possible Dangers: You might lose valuable or even essential items.
Possible Uses: You can get rid of useless key items (Card Key, Pokeflute, etc.) and free up valuable space. And of course, you can get more copies of an item, even faster than the Old Man Trick.