In order to remove the motherboard, the flex cables must be demated

First remove the four flex cables indicated with arrows. Some of the metallic colored tape will need to be peeled back in order to access these.

The flex cables are held in place using ZIF (zero insertion force) connectors.

For the top two and the bottom left (in the photo) the black tab needs to be carefully opened using a plastic prying tool in order to remove the flex cable.

For the bottom right connector, the white tab needs to be carefully lifted up with a plastic prying tool in order to release the flex cable.