You can add boot option for Grub2 for Ubuntu by editing the 40_custom file.
sudo gedit /etc/grub.d/40_custom
Append the following line
menuentry "Ubuntu Mymod" {
recordfail
insmod ext2
set root='(hd3,1)'
linux /boot/vmlinuz-2.6.32-21-generic-pae root=UUID=c01e7d24-fc8c-4498-86a2-ad0ea8d1d4ec ro quiet splash acpi=off noapic nolapic
initrd /boot/initrd.img-2.6.32-21-generic-pae
}
Modify for your own use e.g. the set root if it’s located different or match the system by disabling some of the boot options like ““acpi=off noapic nolapic”
Last we need to set the permission with chmod and update. Add permissions:
sudo chmod +x /etc/grub.d/40_custom
Update the boot loader
sudo update-grub