Memory map is as reported by boot: 0x0 for 639KB 0x100000 for 15360KB I need this in boot.conf to reach all 20MB of installed memory: machine memory +0x400000@0x1000000 # Issue with GENERIC: OpenBSD 4.7 (GENERIC) #558: Wed Mar 17 20:46:15 MDT 2010 deraadt@i386.openbsd.org:/usr/src/sys/arch/i386/compile/GENERIC cpu0: Intel 486DX2 ("GenuineIntel" 486-class) cpu0: FPU,V86 real mem = 20541440 (19MB) avail mem = 9535488 (9MB) mainbus0 at root bios0 at mainbus0: AT/286+ BIOS, date 12/30/93 pcibios at bios0 function 0x1a not configured bios0: ROM list: 0xc0000/0x8000 cpu0 at mainbus0: (uniprocessor) isa0 at mainbus0 isadma0 at isa0 com0 at isa0 port 0x3f8/8 irq 4: ns16450, no fifo com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo com1: probed fifo depth: 0 bytes pckbc0 at isa0 port 0x60/5 pckbd0 at pckbc0 (kbd slot) pckbc0: using irq 1 for kbd slot wskbd0 at pckbd0: console keyboard pmsi0 at pckbc0 (aux slot) pckbc0: using irq 12 for aux slot wsmouse0 at pmsi0 mux 0 vga0 at isa0 port 0x3b0/48 iomem 0xa0000/131072 wsdisplay0 at vga0 mux 1: console (80x25, vt100 emulation), using wskbd0 wsdisplay0: screen 1-5 added (80x25, vt100 emulation) wdc0 at isa0 port 0x1f0/8 irq 14 wd0 at wdc0 channel 0 drive 0: wd0: 16-sector PIO, LBA, 8693MB, 17803440 sectors wd0(wdc0:0:0): using BIOS timings ne2 at isa0 port 0x280/32 irq 9, NE2000 (RTL8019), address 00:60:67:25:b8:b8 pcppi0 at isa0 port 0x61 midi0 at pcppi0: spkr0 at pcppi0 lpt0 at isa0 port 0x378/4 irq 7 npx0 at isa0 port 0xf0/16: reported by CPUID; using exception 16 fdc0 at isa0 port 0x3f0/6 irq 6 drq 2 fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec biomask ed65 netmask ef65 ttymask ffff vscsi0 at root scsibus0 at vscsi0: 256 targets softraid0 at root kernel: protection fault trap, code=0 Stopped at cpu_switchto+0x75: popl %esi ddb> cpu_switchto(d086b654,d0be9000,d0a3ef18,d037af21,d0be9000) at cpu_switchto+0x75 cfdata(d0be9000,d0be9000,0,0,d12b0570) at cfdata+0x45e4 config_attach(0,d08640a4,0,0,d0752477) at config_attach+0xfd config_rootfound(d07524c0,0,d0a3efa0,d03655e1,2) at config_rootfound+0x27 main(0,0,0,0,0) at main+0x4bd ddb> PID PPID PGRP UID S FLAGS WAIT COMMAND 5 0 0 0 2 0x100200 pfpurge 4 0 0 0 2 0x100200 syswq 3 0 0 0 2 0x100200 idle0 2 0 0 0 2 0x100200 kmthread * 1 0 0 0 7 0 swapper 0 -1 0 0 3 0x80200 wdccmd swapper ddb> rebooting... # Working personnal kernel # [maxusers 8, all unused drivers removed, vscsi&softraid removed] OpenBSD 4.7-stable (CPAQ-BIG) #1: Thu Jun 17 22:53:52 EDT 2010 hugov@dolphin.faxmate.com:/home/hugov/src/kernels/compile/CPAQ-BIG cpu0: Intel 486DX2 ("GenuineIntel" 486-class) cpu0: FPU,V86 real mem = 20541440 (19MB) avail mem = 15233024 (14MB) mainbus0 at root bios0 at mainbus0: AT/286+ BIOS, date 12/30/93 bios0: ROM list: 0xc0000/0x8000 cpu0 at mainbus0: (uniprocessor) isa0 at mainbus0 isadma0 at isa0 com0 at isa0 port 0x3f8/8 irq 4: ns16450, no fifo com1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo pckbc0 at isa0 port 0x60/5 pckbd0 at pckbc0 (kbd slot) pckbc0: using irq 1 for kbd slot wskbd0 at pckbd0: console keyboard pmsi0 at pckbc0 (aux slot) pckbc0: using irq 12 for aux slot wsmouse0 at pmsi0 mux 0 vga0 at isa0 port 0x3b0/48 iomem 0xa0000/131072 wsdisplay0 at vga0 mux 1: console (80x25, vt100 emulation), using wskbd0 wsdisplay0: screen 1-5 added (80x25, vt100 emulation) wdc0 at isa0 port 0x1f0/8 irq 14 wd0 at wdc0 channel 0 drive 0: wd0: 16-sector PIO, LBA, 8693MB, 17803440 sectors wd0(wdc0:0:0): using BIOS timings ne2 at isa0 port 0x280/32 irq 9, NE2000 (RTL8019), address 00:60:67:25:b8:b8 pcppi0 at isa0 port 0x61 spkr0 at pcppi0 midi0 at pcppi0: lpt0 at isa0 port 0x378/4 irq 7 npx0 at isa0 port 0xf0/16: reported by CPUID; using exception 16 fdc0 at isa0 port 0x3f0/6 irq 6 drq 2 fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec biomask ed65 netmask ef65 ttymask ffff root on wd0d swap on wd0b dump on wd0b