I recently downgraded AppleUSBAudio.kext from version 10.6.3 to 10.5.6. (The reason for that is because there is a bug with the 10.6 versions of the AppleUSBAudio.kext with certain USB audio devices.) Anyways, I have to manually reload kext upon every restart. (sudo kextload /System/Library/Extensions/AppleUSBAudio.kext) I unloaded the 10.6 kext with kextunload, replaced it, and then reloaded the 10.5 kext and repaired permissions. Still I have to manually reload the kext at every restart. How can I keep the kext loading on startup? I've read the man page on kextload, but it didn't seem to give me any useful info about my case. There must be something obvious I have forgotten!