Wiibrew have gone into further details on current update of system menu 4.2 stating on what has been affected by the update if you are planning or use homebrew software for the wii
The changes are:
* Deletes most homebrew.
* Now uses IOS70. (No Preloader due to that)
* Wii Shop Channel updated. Use WiiSCU to update the shop channel.
* Most of the IOS's have been updated or stubbed.
* Updates your boot2 to boot2v4 (what LU64+'s have). (That means no downgrading of any IOS, and due to that, you can't revert back to your old System Menu. So BootMii as boot2 installed is removed.)
Also the following homebrew is affected:
Bannerbomb Doesn't work. Use Indiana Pwns or Comex's SmashStack beta
BootMii. BootMii will cease to exist. Wait for an update to the HackMii Installer.
Homebrew Channel It is uninstalled with this update.
cIOS Popular piracy cIOS locations are stubs. Don't pirate.
Preloader 0.29 Not loaded any more due to IOS70 being used as the System Menu. Wait for an update.
dcemu will keep you posted as usual if and when these workarounds are available!