NAND

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The DSi uses a 256MB Samsung moviNAND flash chip, which is a NAND flash chip with a built-in controller that implements a MMC (SDIO) interface. In many ways, it's like an SD card in BGA packaging, and some people have successfully read it with modified SD card readers.

Addressing is done in terms of 512-bytes sectors. All wear-levelling and bad-block-mapping is handled transparently inside the chip by the controller. Most sectors are encrypted with a per-console key.

Layout:

Offset Size Description
0 0x200 PC-style MBR, encrypted with a per-console key
0x200 0x200 Stage 2 info block 1 (see below)
0x400 0x200 Stage 2 info block 2
0x600 0x200 Stage 2 info block 3
0x800 0x4DC00 Stage 2 bootloader (encrypted with a universal key)
0x4E400 0x400 Stage 2 footer -- unknown format, but first 10 bytes are build number of Stage 2 bootloader
0x4E800 ? Unused (all 00)
0xffa00 0x400 Factory test area (often contains build date of device in plaintext)
0x10ee00 ? start of per-console unique encrypted data