Booting FreeBSD via GRUB

B

balanga

After install Grub2, I'm unable to boot FreeBSD. The Grub installation is on an Archlinux partition and boots up OK. I couldn't figure out how to get Grub to automatically add FeeBSD so have been struggling to add it manually using whatever guides I could find such as:-

http://unix.stackexchange.com/questions/109272/add-freebsd-to-grub2-boot-menu

I put the following in /etc/grub.d/40_custom on my Arch Linux partition (/dev/sdb3)

Code: 
menuentry "FreeBSD" {
set root='(hd1,2)'
kfreebsd /boot/loader
}

run grub-mkconfig -o /boot/grub/grub.cfg

FreeBSD appears on the Grub menu, but when I select it I get
Code: 
error: not an assignment.
error: file '/boot/loader' not found

Press any key to continue...

I've tried several other guides but none work.

Can anyone suggest what I'm missing?
 
You could try with chainloader, which sometimes works if /boot/loader doesn't.

Code: 
menuentry "FreeBSD" {
set root='(hd1,2)
chainloader (hd1,2)+1
}

Do you have to run grub-mkconfig when you use 40_custom? (I just create a /boot/grub (or grub2, depending upon distribution) custom.cfg which doesn't require a grub-mkconfig afterwards. However, that's ot the issue, that part is just my idle curiosity.

Is the FreeBSD partition definitely on second hard drive's second partition?
 
I'm using a ThinkPad X220 laptop which has an mSATA disk, an internal disk and a USB attached disk, which appears as /dev/da0 in FreeBSD, so I can't be certain how Grub enumerates the disks. The USB disk is first in the BIOS boot order.

I have been running grub-mkconfig -o /boot/grub/grub.cfg using 40_custom where grub is install on a Linux partition.
I'll create a custom.cfg as you suggest and see how it goes.
 
I'm dual booting Linux Mint DE x32 and FreeBSD 11 x32 using grub. Grub is installed in the Mint partition. The /etc/grub.d/40_custom entry that works for me is:

menuentry "FreeBSD 11.0" {
insmod ufs2
set root=(hd0,2)
kfreebsd /boot/loader
}

And then update-grub and reboot.
Hope this helps. Cheers
 
If the device order is changing, you can use the search command to set the root environment variable using the target partition's UUID or, if you have FreeBSD installed on ZFS, using the name of your zpool. For example:

Code: 
search --fs-uuid --set=root --no-floppy 1234567890abcdef
# or
search --label --set=root --no-floppy myzpool
If you are using ZFS, the syntax for specifying file paths in GRUB is also a little bit funky. For example, the file /boot/loader found on a dataset named myzpool/ROOT/mybootenv would be addressed as:

Code: 
/ROOT/mybootenv@/boot/loader
(And, yes, the pool name is supposed to be omitted like that.)

If you're really stuck, the best tool for debugging a problem like this is probably the GRUB command line. It's pretty easy to use if you have a reference handy. Also, grub-probe might be useful; you can use it to get a partition's UUID, test if GRUB can read the target filesystem, among other things.

Good luck.
 
Dean Switzer said:
I'm dual booting Linux Mint DE x32 and FreeBSD 11 x32 using grub. Grub is installed in the Mint partition. The /etc/grub.d/40_custom entry that works for me is:

menuentry "FreeBSD 11.0" {
insmod ufs2
set root=(hd0,2)
kfreebsd /boot/loader
}

And then update-grub and reboot.
Hope this helps. Cheers
Click to expand...

After spending a few days messing with Grub to get it working, my preferred way of installing things is to install FreeBSD first and use pkg install grub2 to install Grub and manually create grub.cfg.

https://forums.freebsd.org/threads/19701/page-2#post-347591

Once I get better acquainted with Grub I'll experiment with the custom entries. One thing I don't understand is what the insmod ufs2provides.. I didn't include it, but things worked... maybe because grub.conf is on a ufs partition.. I also not that chainloader is not required, contrary to what I read in some guides and that kfreebsd should be used instead.
 
Having succeeded in booting FreeBSD via Grub, I am now stuck in my quest for creating multiple boot USB disk. I wanted to create such a universal boot disk for repair/maintenance/installation purposes but soon realised that using a disk partitioned with MBR severely restricts the disk's capability irrespective as to how big the disk is. So I've created a GPT disk and installed FreeBSD, thinking that installing Grub would be straightforward enough, but.....
Code: 
grub-install --boot-directory=/boot /dev/da0
/usr/local/sbin/grub-bios-setup: warning: this GPT partition label contains no BIOS Partition; embedding won't be possible.

Anyone know how to get around this?
 
On a GPT-formatted disk, GRUB looks for a partition with a specific GUID to install its core image to rather than using the traditional post-MBR gap. You can create this partition easily with gpart(8). For example:

Code: 
gpart add -t bios-boot -b 2048 -s 1M -l grubcore da0
Note that this partition doesn't have to be very big.
 
Many thanks for this. Does the GRUB partition have to be the first partition or can it be anywhere on the disk? ie can I add it after I have installed FreeBSD?
 
I'd be inclined to call it a bug if it had to be the first partition. But it's probably not a bad idea given BIOS' traditional addressing limitations.

If you already have FreeBSD installed, there's no harm in tacking a bios-boot partition onto the end and giving grub-install a shot. Resizing your swap partition if you have one is also an easy option if you need to make room.

But there should be plenty of unallocated space in the gap between the GPT header and the first partition. The typical image that gets generated by GRUB doesn't even break 200KiB. Often, 1-2MiB for the partition is suggested, but that's largely for future-proofing and aligning disk reads.
 
I have only just come across the grub2-efi pkg which I believe is what I need to get Grub playing nicely with efi.... Trouble is I can't find an example of how to install it.. apart from
https://forums.freebsd.org/threads/60009/" href="/index.php?threads/https://forums.freebsd.org/threads/60009//">Thread https://forums.freebsd.org/threads/60009/ where this command is used grub-install --target=x86_64-efi --root-directory=/efi /dev/da0... I'm not sure what this '--root-directory' is supposed to specify. I see I have an efi partition but there is not /efi directory. I also note that grub-install() does not include such an option but does not flag it as an error when it is specified.
 
balanga said:
I have only just come across the grub2-efi pkg which I believe is what I need to get Grub playing nicely with efi.... Trouble is I can't find an example of how to install it.. apart from
https://forums.freebsd.org/threads/60009/" href="/index.php?threads/https://forums.freebsd.org/threads/60009//">Thread https://forums.freebsd.org/threads/60009/ where this command is used grub-install --target=x86_64-efi --root-directory=/efi /dev/da0... I'm not sure what this '--root-directory' is supposed to specify. I see I have an efi partition but there is not /efi directory. I also note that grub-install() does not include such an option but does not flag it as an error when it is specified.
Click to expand...
I would recommend that your get better acquainted with GRUB2 first. Really, Not everything is smooth with grub2-efi booting FreeBSD, at least I had problems with X...
 
For my setup with UEFI and GBT
Code: 
menuentry "FreeBSD" {
        insmod ufs2   
        chainloader (hd0,7)/boot/loader.efi 
}
substitute the 7 for the disk partition number (if on MBR also add "msdos" before the number such as "msdos7")
for a BIOS system substitute loader.efi for loader(I have not tested this)
hd0 is the disk this might also need to be changed if multiple disks exist(I don't know how to tell how you should change it)
I am also not sure what to do if you are not on ufs2
 
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