Old Compaq ppro/200 sees only 1/2 its 32mb of RAM

["Eric Kuhnke" <eric@fnordsystems.com>]

Trying 2.9-RELEASE on a Compaq Professional Workstation 5000...  the
machine in question is a ppro/200, 440FX chipset, with a single 32mb EDO
ECC DIMM installed.  During the POST it shows all 32mb, and other OSes see
32mb of RAM.  However, any version of OpenBSD sees only the first 16mb of
RAM.  Same results with GENERIC or custom (driver stripped) kernels.

Anybody else tried openbsd on older (~1997) compaq workstations?

Here's a dmesg:

OpenBSD 2.9 (GENERIC) #653: Sat Apr 28 13:57:59 MDT 2001
    deraadt@i386.openbsd.org:/usr/src/sys/arch/i386/compile/GENERIC
cpu0: Intel Pentium Pro ("GenuineIntel" 686-class, 256KB L2 cache) 199 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SYS,MTRR,PGE,MCA,CMOV
real mem  = 16363520 (15980K)
avail mem = 10252288 (10012K)
using 225 buffers containing 921600 bytes (900K) of memory
mainbus0 (root)
bios0 at mainbus0: AT/286+(0f) BIOS, date 07/14/97
apm0 at bios0: Power Management spec V1.1
apm0: AC on, battery charge unknown
pcibios at bios0 function 0x1a not configured
bios0: ROM list: 0xc0000/0x8000 0xc8000/0x4000
pci0 at mainbus0 bus 0: configuration mode 1 (no bios)
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
ppb0 at pci0 dev 6 function 0 "IBM 82351 PCI-PCI" rev 0x01
pci1 at ppb0 bus 1
tl0 at pci1 dev 11 function 0 "Compaq ProLiant Netelligent 10/100 TX" rev
0x10: irq 11 address 00:80:5f:85:8d:30
nsphy0 at tl0 phy 1: DP83840 10/100 media interface, rev. 1
ukphy0 at tl0 phy 31: Generic IEEE 802.3u media interface
ukphy0: OUI 0x100014, model 0x0001, rev. 5
siop0 at pci1 dev 12 function 0 "Symbios Logic 53c875" rev 0x04: irq 11,
has RAM
siop0: scsi bus reset
scsibus0 at siop0: 16 targets
sd0 at scsibus0 targ 0 lun 0: <COMPAQ, ST34371W, 0388> SCSI2 0/direct
fixed
siop0: target 0 now using tagged 16 bit 10 MHz 15 REQ/ACK offset xfers
sd0: 4094MB, 5172 cyl, 10 head, 162 sec, 512 bytes/sec, 8386000 sec total
vga1 at pci0 dev 11 function 0 "Matrox MGA Millenium 2064W (Storm)" rev
0x01
wsdisplay0 at vga1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
pcib0 at pci0 dev 20 function 0 "Compaq PCI-ISA" rev 0x0c
pciide0 at pci0 dev 20 function 1 "Compaq Netelligent IDE" rev 0x0a: DMA
(unsupported), channel 0 configured to compatibility, chann
el 1 configured to compatibility
pciide0: channel 0 interrupting at irq 14
atapiscsi0 at pciide0 channel 0
scsibus1 at atapiscsi0: 2 targets
cd0 at scsibus1 targ 0 lun 0: <MATSHITA, CD-ROM CR-583, 1.05> SCSI0
5/cdrom removable
pciide0: channel 1 ignored (not responding; disabled or no drives?)
isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
npx0 at isa0 port 0xf0/16: using exception 16
pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
pccom1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
isapnp0 at isa0 port 0x279: read port 0x203
"ESS ES1868 Plug and Play AudioD, ESS0000, , " at isapnp0 port 0x800/8 not
configured
ess0 at isapnp0 "ESS ES1868 Plug and Play AudioD, ESS1868, , " port
0x220/16,0x388/4,0x330/2 irq 5 drq 1,0: ESS Technology ES1868 [v
ersion 0x688b]
ess0: audio1 interrupting at irq 5
audio0 at ess0
opl0 at ess0: model OPL3
midi1 at opl0: <ESS Yamaha OPL3>
biomask 4840 netmask 4840 ttymask 48c2
pctr: 686-class user-level performance counters enabled
mtrr: Pentium Pro MTRR support
dkcsum: sd0 matched BIOS disk 80
root on sd0a
rootdev=0x400 rrootdev=0xd00 rawdev=0xd02