Mini Is Not IOS -- but it is a limited replacement that can fulfill many low-level tasks that IOS might interfere with. The name is an allusion to GNU, which stands for "GNU's Not Unix"

Features

	Mini
General
Author(s)	Team Twiizers
Type	System tool
Links
	Source

Light-weight -- binary is approximately 50kbytes, 11,673 lines of code as of first release
Mostly IRQ driven :)
Supports debug output over the GPIO pins and USBGecko
Supports loading both ARM and PPC-side binaries over USBGecko (ala Wiiload)
Allows any memory address to be peeked or poked from the PPC (via IPC)
Contains drivers for the following hardware:
- OTP, SEEPROM
- AES Engine
- SDHC (at the sector level, or can load a file from a FAT FS on SD)
- NAND (read/write at the physical level)
- PowerPC (can read a PPC ELF file from SD into memory, and kickstart execution on the PPC)
Not dependent on IOS in any way -- as long as you can run it, it can do whatever it wants, regardless of what security features Nintendo patches into newer versions of IOS.

Limitations

No real kernel architecture; no threading model, but most calls are asynchronous
No USB support (including Bluetooth for Wiimotes)
No WiFi support
No NAND FS support
No audio/visual capability (hardware limitation)

All registers are exposed over IPC, so some or all of the missing driver functionality could conceivably be implemented on the PPC side. Note that this cannot execute at the same time as IOS; you can only have one or the other executing at any point in time. Switching back and forth between the two is left as an exercise for the developer.

Since the discovery of the AHBPROT register, Mini enables direct PPC access to all devices. It is often used together with Wii Linux to enable full hardware functionality and performance.

IPC documentation

IPC messages take the following format:

struct {
    u32 code;
    u32 tag;
    u32 args[6];
}

IPC_SYS_PING

Simply pings the Starlet for testing.

IPC_SYS_JUMP

Shuts down mini and jumps to the code passed.

IPC_SYS_GETVERS

Fetches the mini version.

IPC_SYS_GETGITS

Fetches mini's Git version.

IPC_NAND_RESET

Disables and re-enables the NAND Interface.

IPC_NAND_GETID

Retrieves the NAND's physical ID.

IPC_NAND_STATUS

Sends the GETSTATUS command to the NAND.

IPC_NAND_READ

Reads a raw page from the NAND.

IPC_NAND_WRITE

Writes a raw page to the NAND.

IPC_NAND_ERASE

Erases a block on the NAND.

IPC_NAND_SETMINPAGE

Changes the lowest writable page enforced by mini to prevent accidental bricking.

IPC_NAND_GETMINPAGE

Fetches the lowest writable page enforced by mini.

IPC_SDHC_DISCOVER

Initializes the SDHC handler.

IPC_SDHC_EXIT

Shuts off the SDHC handler.

IPC_SDMMC_ACK

Clears the "new SD card" flag, resulting in IPC_SDMMC_STATE returning SDMMC_INSERTED instead of SDMMC_NEW_CARD.

IPC_SDMMC_READ

Reads raw data from the front SD card.

IPC_SDMMC_WRITE

Writes raw data to the front SD.

IPC_SDMMC_STATE

Returns whether there is no SD card (SDMMC_NO_CARD), a card inserted since the last IPC_SDMMC_ACK (SDMMC_NEW_CARD), or a card inserted before the last IPC_SDMMC_ACK (SDMMC_INSERTED).

IPC_SDMMC_SIZE

Returns the number of sectors in the front SD.

MINI

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