Hello ! I disassembled mine today for curiosity, and found out that what you did at step 3 is not the best idea, it could very easily break the plastic. They are meant to be disassembled in the following order: unscrew the 4 screws, lift the round part just enough to remove the 2 connectors (battery and speaker) and then the plastic cover slides back with no effort whatsoever. Also, when putting it back together you must do the same, slide the cover, and then by gently keeping the round portion up, put the 2 connector back. It became clear to me that this is how they assemble them at the factory, because it doesn't click back into place, even when pressed hard, instead the plastic slide starts to crack.