There are a few quirk methods in the driver to nudge devices into the proper mode, but it requires adding your product to a list and recompiling.. usually it involves testing a few of the methods and picking the one that works.
If you're fretting this, a temporary solution that works in some cases is to use
eject(1) in base to send a SCSI command to the virtual cd(4) device.. more specifically, it tells it to "eject the tray" which is often used to indicate you're finished installing the bundled drivers.
So, try this and report back:
$ sudo eject /dev/rcd0c
Posting the full dmesg in [code][/code] blocks is usually a better idea, just so we're sure you haven't missed anything or improperly truncated.