If you have IOS249 installed, that should be your de facto IOS for homebrew and other Wii hacks.
An updated c IOS249 (whether from c IOS36_rev[version], c IOS38_rev[version] or c IOSx_rev[version]) is all you need.
When a new one comes through, just download the new c IOS installer read the instruction and install.
If you have a problem with a newer or buggy c IOS, then just grab an older version's installer file and install it. Here is a diagram on how system IOS's and c IOS's exists / are related.
All customized IOS versions install as an IOS in the 200 range. Installing c IOS is safe because it never modifies your original IOS, it just adds another one.
You can also easily remove the c IOS without adversely affecting the stock functionality of the Wii.
c IOS is quite simply a modified/patched Nintendo system IOS.
IOS37 had some codes built into it that the Wii uses to control the USB Microphone for that game.As stated previously, the IOS for the Wii is NOT firmware.You can think of IOS files as "system files" which are stored on a "system on a chip" or SOC within the Wii. Here's what you really need to know about IOS - the system files that it stores are the codes that the Wii uses to communicate with the Wiimotes, nunchuks, balance board, USB Instruments, DVD Drive, Gamecube Controllers, etc. This is not a how too guide, more of an explanation of "what am I getting myself into." The shot answer is to "un-lock" features of the Wii, that Nintendo never intended us to have. Most methods for making this happen take advantages of exploits in specific games. In this blog, we will discuss everything you need to know about softmodding a Wii.The first disc backup loaders were also borne out of this customized/patched IOS. Because many IOS's co-exist on the Wii, it is possible to grab a stock one, patch and modify it, and add it as a brand new IOS for use with homebrew applications that can use it.