https://dev1galaxy.org/viewtopic.php?pid=12200#p12200

The host is a notebook Acer, i386, with two major operating systems, as follows.

I have the following partitions:
- /dev/sda1 with Devuan Stable (16GB, installed and bootable)
- /dev/sda2 with FreeBSD (~900GB, installed, works, but boots with chainloader)
- /dev/sda3 with Swap (the rest).

Both systems are working as they should.

Grub is working and it is on the first partition.
Grub (on Linux Devuan /dev/sda1) is intended to allow to boot both operating systems. 

Which Grub content would you recommend to boot FreeBSD for  /boot/grub/grub.conf (/dev/sda1) ? 

For Linux, it works since grub does the job, i.e. a regular linux / initrd.
I considered using the chainloader +1 for BSD, but maybe it could be better idea.

Thank you for your inputs

menuentry 'FreeBSD Unix Operating System on sda2' { 
	insmod utf
	set root=(hd0,2)
	chainloader +1
}

menuentry 'Rescue OS (Devuan GNU/Linux sda1)' --class devuan --class gnu-linux --class gnu { 
	load_video
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='hd0,msdos1'
	echo	'Loading Linux 4.9.0-6-686-pae Rescue System ...'
	linux	/boot/vmlinuz-4.9.0-6-686-pae root=/dev/sda1 rw 
	echo	'Loading initial ramdisk ...'
	initrd	/boot/initrd.img-4.9.0-6-686-pae
}