Hitchhiker's Guide to Openbsd

4.13 - Common installation problems
4.13.1 - My Compaq only recognizes 16M RAM
Some Compaq systems have an issue where the full system RAM is not detected by the 
OpenBSD second stage boot 
loader
properly, and only 16M may be detected and used by OpenBSD. This can be corrected either by creating/editing 
/
etc/boot.conf
 file, or by entering commands at the "
boot>
" prompt before OpenBSD loads. If you had a machine 
with 64M RAM, but OpenBSD was only detecting the first 16M, the command you would use would be: 
machine mem +0x3000000@0x1000000
to add 48M (
0x3000000
) after the first 16M (
0x1000000
). Typically, if you had a machine with this problem, you 
would enter the above command first at the install floppy/CD-ROM's 
boot>
prompt, load the system, reboot, and create 
an 
/etc/boot.conf
file with the above line in it so all future bootings will recognize all available RAM. 
http://www.openbsd.org/faq/faq4.html (38 of 43)9/4/2011 10:01:58 AM

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4 - OpenBSD 4.9 Installation Guide
It has also been reported that a ROM update will fix this on some systems. 
4.13.2 - My i386 won't boot after install
Your install seemed to go fine, but on first boot, you see no sign of OpenBSD attempting to boot. There are a few 
common reasons for this problem: 
●
No partition was flagged active in fdisk(8). To fix this, reboot the machine using the boot floppy or media, and 
"flag" a partition as "active" (bootable). See 
here
 and 
here
. 
●
No valid boot loader was ever put on the disk. If you hit "Enter" or answer "w" to the "Use (W)hole disk or (E)
dit the MBR?" question during the install, or use the "
reinit
" option of fdisk(8), the OpenBSD boot record is 
installed on the Master Boot Record of the disk; otherwise, the existing master boot code is untouched. This will 
be a problem if no other boot record existed. One solution is to boot the install media again, drop to the shell and 
invoke 
fdisk(8)
 to update the MBR code from the command line: 
# fdisk -u wd0
Note: the "update" option within the interactive ("-e") mode of fdisk will not write the signature bytes required to 
make the disk bootable. 
●