I am using grub2 and would like to boot using a particular image. I edit /etc/default/grub to have:

GRUB_DEFAULT=2

then do sudo update-grub. I check the /boot/grub/grub.cfg file, it has:

if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="2"
fi

I reboot and the damn thing still uses the first image. (I tried other numbers than 2. I always get image number 0.)

Any suggestion how can I troubleshoot this? Google search indicates I am the only one with this problem.

Can you post your grub.cfg content?

Instead put a line like: