Nintendo DS

microSD preparation

Back up first. Formatting erases everything on the microSD card. Copy off any files you want to keep before you begin, and double-check you have selected the correct drive so you do not wipe the wrong device.

microSD preparation

Your flashcard reads files from a microSD card, so the card has to be formatted correctly before the kernel will boot. This is quick and only needs to be done once.

Choose and verify the card

Use a name-brand microSD, ideally 32 GB or smaller for best compatibility. Run a capacity-test tool to confirm it is genuine, since fake cards report false sizes and corrupt data.
Format as FAT32

Connect the card to your computer and format it as FAT32. Most flashcards expect FAT32, not exFAT. A 32 KB allocation unit size is a safe default.
Mount cleanly

Once formatted, the card should appear as an empty drive. You are now ready to copy the card's kernel onto it.

Tip

Keep the card's filesystem tidy. Avoid filling it to the brim, and always eject safely from your computer so the partition stays healthy. fat32

With a clean, verified card ready, continue to Installing the card kernel.