The 8 pin cable to the gimbal. As far as the shell, after removing the required screws, I use those blue cell phone tools to wedge along the edges of the arms. These tools are perfect, as they pull against the top half, while pushing in the bottom half. Once the snaps pop, I use wooden sticks between the top and bottom shells to keep them from snapping back together, while moving them towards the center of the bird to create constant tension for the next snap set. Leave the snap above the battery housing for last. When the two shells separate, you can then wedge the GPS connector out, and you're done.