I have been trying to rework a lead-free BGA. For some reason, when I remove the BGA the corner pads on the board come off and the board must be scrapped. If I do manage to remove the BGA successfully, when I solder the BGA, the corners of the BGA warp up and doesn't allow me to get a good connection on the pads. I have tried using a larger nozzle, increased temperature, and nothing seems to work. the board is ENIG and it does contain a large ground plane.