Article in English: In some phones—typically Samsung brands—you need to remove a second back piece to access your speaker openings. These phones will have 10 to 13 more screws to remove, although the exact number varies by model and manufacturer. Use a #3 Phillips 4 inch (10 cm) screwdriver to turn each screw counterclockwise until they come loose. Afterward, pull off the second back piece.  Pull of the plastic film covering the screws if your phone has one. Once the second back piece is off, you can access and clean speaker openings and speakers. However, in some cases you will only be able to clean the openings. Snap the back piece back on when you're finished cleaning the speakers and reattach the screws. Afterward, you can reattach the metal covers to the speakers and snap the back lid back on.

Summary in Vietnamese:
Tháo lớp nắp lưng phụ nếu bạn vẫn không thể lấy loa ra.