1

In a persistent USB install of Linux Mint 20.3, I want to change grub.cfg to include a timeout (GRUB_TIMEOUT=10).

If I edit /etc/default/grub and run sudo update-grub, I get the error: failed to get canonical path of /cow. This is to be expected, since it shouldn't work on a live install (see https://askubuntu.com/questions/1292151/sudo-update-grub-failed-to-get-canonical-path-of-cow-why )

Is there a way to do it? In particular, is it possible to boot the USB persistent Linux Mint and change from there the grub configuration? I don't want to override any configuration of the host machine drives, I only want to change the grub of the USB Linux Mint persistent install


EDIT: I think I found the correct file under /cdrom/boot/grub/grub.cfg, this should be the mounted drive for grub. Can I simply add a line there saying GRUB_TIMEOUT=10? This is what it currently has:

if loadfont /boot/grub/font.pf2 ; then
        set gfxmode=auto
        insmod efi_gop
        insmod efi_uga
        insmod gfxterm
        terminal_output gfxterm
fi

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

menuentry "Start Linux Mint 20.3 Cinnamon 64-bit" --class linuxmint {
        set gfxpayload=keep
        linux   /casper/vmlinuz  persistent file=/cdrom/preseed/linuxmint.seed boot=casper iso-scan/filename=${iso_path} quiet splash --
        initrd  /casper/initrd.lz
}
menuentry "Start Linux Mint 20.3 Cinnamon 64-bit (compatibility mode)" {
        linux   /casper/vmlinuz  persistent file=/cdrom/preseed/linuxmint.seed boot=casper iso-scan/filename=${iso_path} noapic noacpi >
        initrd  /casper/initrd.lz
}
menuentry "OEM install (for manufacturers)" {
        set gfxpayload=keep
        linux   /casper/vmlinuz  persistent file=/cdrom/preseed/linuxmint.seed oem-config/enable=true only-ubiquity boot=casper iso-sca>
        initrd  /casper/initrd.lz
}
menuentry "Check the integrity of the medium" {
        linux   /casper/vmlinuz  boot=casper integrity-check iso-scan/filename=${iso_path} quiet splash --
        initrd  /casper/initrd.lz
}

1 Answer 1

0

It's not possible to change /cdrom , i.e., the boot partition, because it is mounted as read-only and is always busy, so can't be unmounted.

You need to boot with a different system, mount this partition and then edit the /boot/grub/grub.cfg file to add a new line: set timeout=10 (where 10 is the number of seconds for the timeout)

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .