Just finished the experiment. Rebooting does not help.
Code:
scsibus: -2 target" -2 lun -2No such file or directory. Cannot open 'cd0c'. Cannot open or use SCSI driver.
The same using rcd0c.
Code:
egrep "^cd.+ at scsibus" /var/run/dmesg.boot
from share/doc/cdrtools/README.OpenBSD. shows the device to be rcd0, but using cd and rcd yield the same result.
I am off to bed.