If your console is no longer reading Micro SD memory or it is intermittent, then it is possibly time to replace the memory card reader slot.
The SD card comes premounted on its own board with ribbon flex for connecting it to the mainboard, it uses a press fit connector making it a plug and play replacment module, no soldering is required.
This part is ideal for repairing a New 3DS XL / LL which no longer reads SD cards or if the ribbon has been damaged during a repair.
What's in the Box
1x Micro SD card reader