Remember the gold foil I pointed out in step 10? Go to the right and see where I marked the arrow. Start to pull off the gold foil under the cable and don't tear it apart.

Go slow!

Remove the foil. You will see there is also a light blue foil as shown in the second picture. It's attached to the gold foil. Leave it attached!

Once you detached the gold/blue foil, remove the flex cable that lies beneath the black foil that covers the battery compartment. In the first picture I marked red lines show where the flex cable lies.

You have to tear it and it won't glue again.

Once you removed the flex cable it looks a little bit like a scorpion there :)