Loosen the two #0 Phillips 4.2 mm-length screws located at the top of the back cover.
The screws have locking washers that prevent the screws from falling off of the back cover. Leave these locking washers on the screws; it is not necessary to remove the washers for this repair guide.
Make sure the SD card has been removed. With a plastic opening tool pry off the lower case starting at the bottom edge and working around the perimeter.
Two ribbon cables connect the case to the circuit board. Be careful to not pull the case too hard and rip the ribbon cables.
Using a plastic opening tool pop off the circle pad joystick.
Do not use excessive force with the plastic opening tool. There is a ribbon attaching the circle pad joystick to the motherboard that will remain attached.
There is a loose washer located in between the circle pad joystick and the circle pad. Use caution and do not lose this piece.
Position the device such that the game cartridge slot is located at the top.
Locate the IR board located on the upper right side of the motherboard.
The IR board is installed upside-down in these photos by mistake. Installing it this way will result in your DS failing to start. Note the orientation of your IR board before you remove it, and reinstall it the same way.
Remove the IR board with a plastic opening tool by inserting the tool below the IR board and gently prying up.
Using a plastic opening tool, pry off the Wi-Fi board.
The Wi-Fi board will still be connected by a wire and it is not necessary to completely remove it for this step. Simply place it out of the way for this step.
Open the hinge and carefully pop off the Upper LCD using your fingers.
Gently remove the ribbon from the hinge.
Though not required, the task of removing the ribbon cables becomes much easier once you remove the hinge barrel on the right side of the device.
Do not lose the tiny fabric and rubber water-resistant rectangles that cover the two speakers; they often fall out once the speakers are removed.
The screen's cover glass can be replaced or transferred to your new screen. The cover is easily scratched by metal tools; use plastic or your fingernail to separate it.
Adhere the cover to the new screen by using thin adhesive around the edges, or by reusing the old adhesive.
To reinsert the hinge piece, open the console to the last click before it's completely flat.
Note: If your top or bottom screen was working before disassembly and doesn't work after reassembly, then it's likely that the connector is loose or dirty or damaged or not clipped or PLACED UPSIDE-DOWN. I had this issue with my Super3DS XL(2015) and it turns out that the reason why my top screen wasn't working after put together, was because I had the top LCD connector upside-down. After I correctly put the connector in, It worked again! :)