Grub2 configuration is not booting menu entry

I messed up a lot; and, here I am.
The grub.cfg custom entry I have is:

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry  'FreeBSD' --class frebsd --class bsd --class os {
                insmod part_msdos
  insmod ufs2
  set root=" (hd0,msdos2,bsd1) "
  kfreebsd /boot/loader
}
### END /etc/grub.d/40_custom ###

And it is not booting.