Post by AskforI am trying to install 7.02 on old 32-bit x86 laptop. I have primay
partition marked as type FreeBSD, in absence of better designation,
It appears that installer accepts it as location, but keeps asking me
for permission to change MBR. I am getting nervous when someone mentions
MBR. What is installer trying to do ? I have other things on that disk.
Is it trying to install some sort of boot loader into MBR ?
I also have some prior experience with FreeBSD. At that point I'd expect
installer to start asking about slices and mount points.
A few days ago, I installed NetBSD on a 32bits machine where I already have Ubuntu with GRUB and here is what I did:
I said “No” when the installer wanted to modify the MBR (like you, it frightens me).
In Ubuntu, I changed `/etc/grub.d/40_custom` to add this:
menuentry "NetBSD" {
savedefault
insmode ufs
set root=(hd0,2)
knetbsd /netbsd --root=wd0f
}
`(hd0,2)` because I installed it on the BIOS second partition, and `wd0f` this what NetBSD mount as root. `wd0f` is a slice, `wd0b` is the whoe BIOS partition and it does not work with it.
You may need to adjust `(hd0,2)` and `wd0f` to match yours. Ensure `/etc/grub.d/40_custom` is executable and run `sudo update-grub`, then reboot to test.
It was working, but I wanted to start NetBSD with chain‑load, which is cleaner (to me at least).
In Ubuntu, I changed again `/etc/grub.d/40_custom` to now have this:
menuentry "NetBSD" {
savedefault
set root=(hd0,2)
chainloader +1
}
I did an `update-grub` and tested with a reboot, It was no working, GRUB complaining the sector signature or something like that was not OK. It was meaning the PBR (Partion Boot Record) was not OK.
To write a proper PBR without touching the MBR, from NetBSD (I temporarily restored the previous `/etc/grub.d/40_custom`, for this), I did this:
cp /usr/mdec/boot /boot
dumpfs -s /dev/rwd0f # To check it’s the device mounted as `/`
installboot -v /dev/rwd0f /usr/mdec/bootxx_ffsv2
Search for the man page about `installboot` to learn more about this key command.
Then I rebooted (with the second `/etc/grub.d/40_custom`), and GRUB was not complaining anymore, and NetBSD started properly, its own way. As a Bonus, I now have a menu for NetBSD boot methods, which you can edit in `/boot.cfg`.