you potentially messed up the ribbon cable from the battery to the adapter. I have done it before. Its not fun...

I have had my iPhone 4 for about 3 and a half years now. I replaced my battery though Ifixit every time It works flawlessly. My speaker enclosure went out and you guys were there to help yet again! Thank you so much for having parts!!!! You have saved my bacon with all of the parts and guides.

Oh and the replacing of the speaker for the iPhone 4 is not that hard its just takes concentration. The reason you want to disconnect the battery is so you don't fry your phone by accidentally touching the screwdriver to the board.