Did you run "sudo update-grub" after adding the entry into 40_custom? It won't be incorporated into the Grub2 menu until this is done.
Originally Posted by Squigglebird
Is 40_custom executable? I don't think this is your only entry in 40_custom, but make sure the executable bit is set:
To have visual confirmation that the file content is being added, you can add this line to the top section of the 40_custom file. When you run "sudo update-grub" in a terminal, you will see a message as the file is read into grub.cfg:
sudo chmod +x /etc/grub.d/40_custom
If you have more than one entry in 40_custom, but only one is showing up in the menu, check to make sure the menuentry is correct (punctuation, etc). If you aren't sure, post it here.
echo "Adding 40_custom." >&2
exec tail -n +3 $0
# 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.