Wii:CIOS Installation

CIOS (Custom IOS) is an umbrella term for any modified-from-official IOS, but in most contexts it primarily refers to major modifications adding features such as software optical disc emulation (used by Wii USB loaders), reading backup discs, or NAND filesystem redirection (i.e. "light", CIOS-based emunand). Other Wii innovations such as USB2 support originated in CIOS; most also provide classic homebrew patches (trucha bug, ES_Identify, NAND Permissions, etc.)

Theory
CIOS is traditionally installed in "slots" 200 (i.e. IOS200, titleID 00000001-000000C8) and above, excluding IOS254 (BootMii-IOS) and IOS255 (temporary title for very old PatchMii-based utilities). By historical convention, the default CIOS is the one installed in slot 249 (00000001-000000F9). It is important to understand, however, that the slot in which any [C]IOS is installed is irrelevant as long as it can be selected by the desired application - the CIOS "brand" and version (therefore the patches applied) and the "base" IOS to which the patches are applied are what define compatibility.

The original CIOS249 was developed by Waninkoko, evolving into CIOSX (referring to the ability to assemble it from a variety of "bases"); his work was competed/supplemented by Hermes's CIOS222 and Tantric's CIOS202. Nowadays, they are generally considered superseded for all purposes by the d2x (davebaol-xabby666-XFlak, now joined by blackb0x) team's CIOS.

d2x CIOS had long been divided into a main branch (v8, v10.52) and an alternate one (v9, v10.53), trading off compatibility with increased USB freedom. d2x v11, which is what the following procedure will install, debuted at the end of 2022 and is based off the former, adding compatibility with RiiConnect24 patches and uStealth.

In his own words, blackb0x recommends:
 * Slot 248 base 38: only bases 38 & 58 can play SpongeBob's Boating Bash, and only 38 has USB keyboard support for Animal Crossing
 * Slot 249 base 56: plays majority of games and a few that base 57 cannot; preferred for slot 249 to avoid unnecessary IOS reloads under USB Loader GX's Auto IOS setting
 * Slot 250 base 57: plays majority of games and a few that base 56 cannot
 * Slot 251 base 58: only bases 38 & 58 can play SpongeBob's Boating Bash, and only 58 supports the LAN adapter (sic)

Requirements

 * A Wii with a connection to the internet.
 * An SD Card or USB drive
 * d2x cIOS Installer

Installation Instructions
You should be connected to the internet for this to work.
 * 1) Download d2x Installer and extract it's contents to your SD Card or USB drive
 * 2) Put the SD card or USB stick into your Wii and launch d2x from the homebrew channel
 * 3) Press continue, afterwards you'll see a screen with a bunch of options, set them to the following.
 * 4) * Select cIOS: d2x-v11-beta1
 * 5) * Select cIOS base: 38
 * 6) * Select cIOS slot: 248
 * 7) * Select cIOS version: 65535
 * 8) Once that is done, press A twice. It will then begin installing our first cIOS.
 * 9) When finished, press A to return to the main screen, set the options to the following:
 * 10) * Select cIOS: d2x-v11-beta1
 * 11) * Select cIOS base: 56
 * 12) * Select cIOS slot: 249
 * 13) * Select cIOS version: 65535
 * 14) Once that is done, press A twice. It will then begin installing our second cIOS.
 * 15) When finished, press A to return to the main screen, set the options to the following:
 * 16) * Select cIOS: d2x-v11-beta1
 * 17) * Select cIOS base: 57
 * 18) * Select cIOS slot: 250
 * 19) * Select cIOS version: 65535
 * 20) Once that is done, press A twice. It will then begin installing our third and final cIOS.
 * 21) When finished, press A to return to the main screen, then press B to exit. You have now installed cIOS and are ready for loading games via USB through homebrew such as USB Loader GX, Wiiflow Lite, and Configurable USB Loader.