GRUB_SAVEDEFAULT how does it work?

[Chris Murphy]

Based on the Grub2 manual, it is not clear to me how GRUB_SAVEDEFAULT=true with 
GRUB_DEFAULT=saved options are supposed to work. The description for 
GRUB_SAVEDDEFAULT says when true and when GRUB_DEFAULT=saved, that "when an 
entry is selected, save it as a new default entry for use by future runs of 
GRUB." It also says the option relies on the environment block.


1.
/etc/default/grub contains

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

2.
I have run grub2-mkconfig -o /boot/grub2/grub.cfg. Header reads as follows.

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
set default="${saved_entry}"
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

3.
grub2-editenv list

<empty>
The file exist, is 1024 bytes, but contains nothing according to this command.

4.
/boot/grub2 is on an ext4 volume.


So I'm not sure what needs to be done to make it work.

System and version info:
Fedora 16 x86_64
GRUB2 1.99-13.fc6.x86_64

Any suggestions?


Chris Murphy