1. give the item you wish to duplicate to a poke in your party

2. deposit the poke with the item into a box

3. switch boxes, and say yes when it asks whether you want to switch boxes

4. when the message "saving, don't turn off the power" normally appears, turn it off somewhere between the words "turn" and "off". the item + poke will be in the box, and in your party when you turn it on again.

Edit: post #900