With the screws taken off from the upper PCB, it's time to desolder the connecting pins that connect the upper PCB to power PCB. My preferred method was to use a desoldering braid but I think a solder sucker works too.

Careful not to let your soldering iron touch the plastic ribbon cable or the upper shell connector (white in the first photo). You can see I did singe my ribbon cable a little bit haha...

Once you've removed the solder from all the pins, you should be able to lift the upper PCB off easily.