malabar // deploy netbsd ext2fs on bare-metal with mdec/mbr (FAIL)

THIS IS A DRAFT – FAIL: bootxx_ext2fs gets wiped out by gnu/linux fsck.ext2

tested on scaleway dedibox with bionic as a rescue system

requirements

export LANG=C
export LC_MESSAGES=C
alias ll='ls -alhF'
apt update
apt install -y man-db manpages mlocate binutils

freaking ubuntu — it mounts the swap space if it finds one

swapon -s
swapoff -a

and proceed

source=http://ftp.fr.netbsd.org/pub/NetBSD/NetBSD-8.0/amd64/
#source=http://ftp.fr.netbsd.org/pub/NetBSD-daily/netbsd-8/201903100010Z/amd64

wget $source/binary/kernel/netbsd-GENERIC.gz
wget $source/binary/kernel/netbsd-INSTALL.gz
zcat netbsd-INSTALL.gz > netbsd

wget $source/binary/sets/base.tgz
#wget $source/binary/sets/base.tar.xz
mkdir base/
tar xzphf base.tgz -C base/
#tar xJphf base.tar.xz -C base/
ls -lF base/usr/mdec/mbr
ls -lF base/usr/mdec/bootxx_ext2fs
ls -lF base/usr/mdec/boot

watch for possible errors

strings base/usr/mdec/mbr
strings base/usr/mdec/bootxx_ext2fs
strings base/usr/mdec/boot

start clean

mount | grep sda
#umount /mnt/dev/
#umount /mnt/
#dd if=/dev/zero of=/dev/sda bs=1M count=1

mbr

THIS WILL ERASE THE PARTITION TABLE AS WELL (512 bytes)

dd if=base/usr/mdec/mbr | hexdump -vC
dd if=base/usr/mdec/mbr of=/dev/sda
#dd if=base/usr/mdec/mbr of=/dev/sda bs=1 count=440

dos partitions

note - netbsd mbr wants a9

not sure we really need to force sector 63

#fdisk -c=dos -u /dev/sda
#o
#n p 1 63 +25G
#t a9
#a

cfdisk /dev/sda

25G a9 BOOTABLE

build the filesystem without -r 0 as largefiles is available now

mkfs.ext2 -O^dir_index /dev/sda1
tune2fs -l /dev/sda1 | grep features:

gives

ext_attr resize_inode dir_index filetype sparse_super large_file

secondary boot strap & kernel

mount /dev/sda1 /mnt
cp base/usr/mdec/boot /mnt/
cp netbsd-GENERIC.gz netbsd-INSTALL.gz netbsd /mnt/
umount /mnt

primary boot strap

everything is almost zeroes so far in sectors 0,1,2-11

dd if=/dev/sda1 count=13 skip=0 | hexdump -C | less

backup the first sectors of the partition

dd if=/dev/sda1 of=sda1.13sec.bkp count=13
ls -lF sda1.13sec.bkp # 6656 bytes

WRITE

dd if=base/usr/mdec/bootxx_ext2fs of=/dev/sda1

#DO NOT
#fsck.ext2 -y /dev/sda1

#ext2fs_open2: Bad magic number in super-block
#fsck.ext2: Superblock invalid, trying backup blocks...

check and compare against the 13 blocks long pbr+bootxx

dd if=/dev/sda1 count=1 skip=0 | hexdump -vC
dd if=/dev/sda1 count=1 skip=1 | hexdump -vC
dd if=/dev/sda1 count=11 skip=2 | hexdump -vC | less

dd if=base/usr/mdec/bootxx_ext2fs count=1 skip=0 | hexdump -vC
dd if=base/usr/mdec/bootxx_ext2fs count=1 skip=1 | hexdump -vC
dd if=base/usr/mdec/bootxx_ext2fs count=11 skip=2 | hexdump -vC | less

FOUND PROBLEM – that part has been wiped by fsck.ext2

#hexdump -vC base/usr/mdec/bootxx_ext2fs | less
#dd if=/dev/sda1 count=13 | hexdump -vC | less

mount /dev/sda1 /mnt
diff base/usr/mdec/boot /mnt/boot
diff netbsd-GENERIC.gz /mnt/netbsd-GENERIC.gz
diff netbsd.gz /mnt/netbsd.gz
diff MD5 /mnt/MD5
diff netbsd /mnt/netbsd
umount /mnt

FAIL – got this (no boot prompt)

NetBSD MBR boot
Error no magic

==> this string is from base/usr/mdec/bootxx_ext2fs meaning that we cannot reach the secondary bootstrap

ready to go

cd ~/
sync
mount | grep sda
umount /mnt/dev
umount /mnt

and finally switch the dedibox to normal mode

troubleshooting

NetBSD MBR boot
Error no slice

==> needs a9/netbsd DOS partition, not 83/linux

resources

Chapter 2. Installing NetBSD: Preliminary considerations and preparations https://www.netbsd.org/docs/guide/en/chap-inst.html

how netbsd boots on x86 https://wiki.netbsd.org/how_netbsd_boots_on_x86/

https://linux.die.net/man/1/hexdump

http://cvsweb.netbsd.org/bsdweb.cgi/src/usr.sbin/installboot/

mbr, bootselect Master Boot Record bootcode http://netbsd.gw.com/cgi-bin/man-cgi?mbr+8

boot system bootstrapping procedures http://netbsd.gw.com/cgi-bin/man-cgi?boot+8

boothowto, BOOT_FLAG flags passed to kernel during boot or shutdown http://netbsd.gw.com/cgi-bin/man-cgi?boothowto+9

options Miscellaneous kernel configuration options http://netbsd.gw.com/cgi-bin/man-cgi?options+4

userconf in-kernel device configuration manager http://netbsd.gw.com/cgi-bin/man-cgi?userconf+4

installboot install disk bootstrap software http://netbsd.gw.com/cgi-bin/man-cgi?installboot+8

NOT NEEDED boot.cfg configuration file for /boot http://netbsd.gw.com/cgi-bin/man-cgi?boot.cfg+5