Mii Maker

Mii Maker lets you create Miis, like Wii Mii Channel. Here you can transfer Miis locally from other 3DSes, or from Wii Mii Channel. 3DS Miis can't be transfered to Wii Mii Channel, only from Wii.

Wii Mii Channel transfer protocol

The Wii beacons are similar to the usual multi-cart NDS beacons, except: beacon_type is zero, and payload size is 0x14. The payload data is just the Wii UTF-16 nickname, with some extra unused zero data. The usual multi-cast NDS protocol is used for sending the 3DS nick to the Wii. After many keep-alive frames, it eventually sends a bunch of frames, each containing the whole Mii. There's a 6-byte header, followed by Mii data. At the end of these frames like most NDS frames is the 0200 byte marker.

Mii QR Code format

3DS Mii QR is a standard 57x57 pixel Level 10 High ECC QR code with 'Mii' logo in center (refer to Denso-Wave Inc web site for QR Code format specifications). It contain 112 byte of binary data. 3DS seems to have fully implemented QR-code decoder, as it can interpret such Mii binary data being encoded even in the smallest possible for that data size Level 6 Low ECC QR code. The data itself is encrypted, presumably AES-CTR since some xorpads can be determined from known plaintext here. The CTR might be based on data stored here?

Offset	Length
0x0	0x4	Mii ID (big-endian 32-bit unsigned integer) The most significant 3 bits determine whether the Mii is Special, Foreign, or Normal [1] time_offset = (mii_id & 0x0FFFFFFF) * 2; time_offset is the time the Mii was created, represented as the number of seconds since 01/01/2010 00:00:00
0x4	0x4	High 4 octets of MAC address [2]
0x8	0x10	unknown
0x18	0x2	Bit-mapped: Birthday (4bit-day,5bit-month), Sex, Shirt, ??
0x1A	0x14	UTF-16 Mii Name
0x2E	0x1A	unknown
0x48	0x14	UTF-16 Author Name
0x5C	0x2	unknown
0x5E	0x2	unknown (seems like the start of the checksum)
0x60	0x10	AES-CCM MAC?

• Codes made from the same 3DS for the same Mii are encrypted with the same xorpad (you can recreate it by xoring with known values from this table).