I quickly regretted not having read the comments to this step and the next one. When replacing the power/sensor cable, this step isn’t necessary, provided you are careful enough with the earpiece speaker and the sensors which are next to the front facing camera.
DO NOT DO THIS unless you are sure you have to. This step and the next one are not necessary when replacing the power and sensor cable.
It is very very difficult to fix the front camera retainer again after removing it.