I'm attempting to make a serial console install disk using the 
no-emulation boot sector provided.  Following 
http://www.openbsd.org/cgi-bin/cvsweb/src/distrib/i386/cdfs/Makefile?rev=1.7&content-t..., 
I can see that you do a standard dirctory setup as shown below (I've 
essentially just copied my 4.2 CD disk1 in this case) and I've modified 
boot.conf to include the necessary "set tty com0" line:

ceidem@adams /home/ceidem$ ls 
bsd42/                                                                           
 
4.2 etc

ceidem@adams /home/ceidem$ ls 
bsd42/etc/                                                                       
 
boot.conf

ceidem@adams /home/ceidem$ cat 
bsd42/etc/boot.conf                                                             
 
set image /4.2/i386/bsd.rd
set tty com0

ceidem@adams /home/ceidem$ ls 
bsd42/4.2/                                                                       
 
i386     packages

ceidem@adams /home/ceidem$ ls 
bsd42/4.2/i386/                                                                  
 
INSTALL.i386  base42.tgz    bsd.rd        comp42.tgz    floppyC42.fs  
misc42.tgz    xfont42.tgz
INSTALL.linux boot.catalog  cd42.iso      etc42.tgz     game42.tgz    
pxeboot       xserv42.tgz
MD5           bsd           cdboot        floppy42.fs   index.txt     
xbase42.tgz   xshare42.tgz
TRANS.TBL     bsd.mp        cdbr          floppyB42.fs  man42.tgz     
xetc42.tgz

I then create an ISO image using the following command:

ceidem@adams /home/ceidem$ mkhybrid -a -R -T -L -d -D -N -o bsd42ser.iso 
-v -v -b 4.2/i386/cdbr -c 4.2/i386/boot.catalog ./bsd42/

or I'll use

mkhybrid -R -T -o bsd42ser.iso -no-emul-boot -v -v -b 4.2/i386/cdbr -c 
4.2/i386/boot.catalog ./bsd42/

on my Linux box.  Either case provides a functional, bootable disk but 
without the serial console.  What am I misunderstanding and/or missing? 

Thanks in advance,
 - chris