Subject: Re: customizing boot-big.fs
To: Sebastian Krohn <>
From: Tracy Di Marco White <>
List: current-users
Date: 01/10/2003 14:22:22
Sebastian Krohn <> wrote:
>Petter Lindquist <> wrote:
>> Is there a quicker way to fiddle with the boot-big.fs than doing a
>> complete -d?
>> All I want is to change the kernel....
>If you already have an image you can mount it via a vnd-device.
>(see vnconfig(8))
>I did this with boot-big.fs from the NetBSD live-CD some time ago.

I build bootable ISOs semi-regularly, and I use these notes:
# creates a file the correct size for a 2.88MB floppy image
dd if=/dev/zero of=boot.tmp count=5760

# uses the disktab for floppy288 to configure a pseudo disk device
vnconfig -t floppy288 -v -c /dev/vnd0d boot.tmp

# install an ffs disklabel
disklabel -rw /dev/vnd0d floppy288

# newfs so it looks like a floppy
newfs -B le -m 0 -o space -i 204800 -c 80 /dev/rvnd0a floppy288

# For setup on serial console uncomment:
#/usr/mdec/installboot -v -f /usr/mdec/biosboot_com0.sym /dev/rvnd0a

# For setup using video card uncomment:
/usr/mdec/installboot -v -f /usr/mdec/biosboot.sym /dev/rvnd0a

# mount the floppy image
mount /dev/vnd0a /mnt

# copy the kernel into the image
cp /usr/src-1.5/sys/arch/i386/compile/SNORT/netbsd /mnt/netbsd

# unmount, unconfigure the pseudo disk device, and move into CD build area
umount /mnt
vnconfig -u /dev/vnd0d
mv -f boot.tmp /usr/snort/boot