We will start by heating the back of the phone to soften the adhesive that holds the lid. When it is hot, we will introduce an opening tool that by sliding it around, we will remove the adhesive.

Remove the sixteen screws that hold the casing and remove the SIM / SD tray. Now we can unlock it by levering with an opening tool.

Only the pushbutton of the intermediate casing remains to detach and disengage.