OK, turns out the model=imac24 does work on Intrepid, it just needed a reboot ("rmmod snd-hda-intel && modprobe snd-hda-intel" without gdm running wasn't enough for some reason, though that did activate it on jaunty).
OK, turns out the model=imac24 does work on Intrepid, it just needed a reboot ("rmmod snd-hda-intel && modprobe snd-hda-intel" without gdm running wasn't enough for some reason, though that did activate it on jaunty).