FWIW, if you change /etc/grub.d/10_linux, you don't need to make grub.cfg unwritable - /etc/grub.d/10_linux is an input to update-grub, not an output from it, and furthermore it's a conffile so changes to it are preserved on upgrade.
FWIW, if you change /etc/grub. d/10_linux, you don't need to make d/10_linux is an input to update-grub,
grub.cfg unwritable - /etc/grub.
not an output from it, and furthermore it's a conffile so changes to it
are preserved on upgrade.