I have a machine which installed a ubuntu 16.04 on one partition and a ubuntu 16.10 on another. I have a 200m partition which mounts /boot/efi.
Basically I use 16.04 and use the grub installed by 16.04.
Sometimes I get on 16.10 and update the kernel. However, I cannot update the grub of my 16.04 without entering it. So I have to do grub-install on 16.10 in order to boot the new kernel. Then when I come back to 16.04, I update-grub and grub-install, which is stupid I think.
How can I update the grub of 16.04 without entering it, is there a good solution?
Can I do something like updating the grub config file or using another partition as /boot? Is this kind of operation dangerous?