COMPAT-BS

COMPAT-BS is used when booting into WiiMode in HAI mode. It's a PPC Ancast image named "boot.bin" and is part of OSv1.
Since in HAI mode the Wii System Menu isn't loaded, it does several tasks usually done by the System Menu.

It comes with its own version of BS2, which loads discs emulated by HAI-IOS.