IOS

IOS (IOP Operating System) is the official firmware running on the Starlet (known officially as the IOP) in the Wii. The distinct software running on the Wii U's Starbuck (also known officially as the IOP) is also known as IOS, but referred to by the community as IOSU to distinguish it from the Wii's version.

Modern versions of Wii-Linux cannot boot under IOS. Very old versions were able to, but this caused many drivers to be duplicated unnecessarily (to have versions that used IOS IPC calls instead of direct hardware access), and was later removed. NPLL will automatically reload into MINI if booted under IOS. NetBSD can run under IOS (if started with AHB access enabled (HW_AHBPROT=ffffffff)) at the cost of lower available memory (since IOS uses 12MB for itself).