Apple today released GarageBand 4.1.2 which improves overall stability and addresses issues with the automation of software instrument parameters, FireWire and USB based audio devices and Magic GarageBand.
GarageBand 4.1.2 is available via Software Update and also as a standalone installer.
More info and download link (19.1MB) here.
[Thanks to MacDailyNews Reader “Ken L.” for the heads up.]