IOS21 is most commonly used by third-party games. It also contains some PowerPC binary in content 1, identical to the one in IOS15. Most debugging messages have been removed, though.
It probably had the connection fixes advertised for 2.2. Many games such as Wii Sports were also rereleased under this IOS with a newer strap screen, probably in response to TVs getting smashed.
This IOS was used by older versions of DataChk, a factory title.
|Version||Signing bug?||/dev/flash access?||ES_Identify?||STM Release Exploit?||Notes|
|v512||Yes||Yes||Yes||Yes||Lowest version released, but not the first release. Released on Mario & Sonic at the Olympic Games in November 2007.|
|v517||Yes||Yes||Yes||Yes||First release; 2.2 update|
|v1295||No||No||No||No||Only found on vWii and newer RVL-101 units.|
|v26895||No||No||No||No||Only found on Wii mini|