Do you mean R4i Gold 3DS Plus?
Your flashcart SD should look like this (from Wood_R4iGold_V1.64.rar):
SD:
├─── __rpg
│.....├── cheats
│.....├── […]will not write all folders
│.....├── ui
│.....├── globalsettings
│.....├── […] and files here
│.....├── updater
├─── _DS_MENU.DAT
├─── [somePlaceForYourRoms]
In any case (no matter what flashcart) Other things to check:
- Is the micro-SD formatted FAT32?
- Have you checked the micro-SD for hardware defects/fake? Windows, Linux, OS X
- Try another FAT32 formatted micro-SD anyway.
- Does the N3DSXL boot any DS software (retails carts or the DS version of “Download Play”)?