I have installed first Kubuntu (sda3), then installed Ubuntu (sda4) and finally Linux Mint (sda5) on the same SSD (back to back). I want to remove Linux Mint from the disk and from the grub menu. But since I have installed Linux Mint as final, grub customization works only on Mint.
I plan to remove sda5 partition but I am afraid if I lose the grub menu. How can I safely remove Linux Mint (sda5) and get control of the grub menu to Ubuntu (sda4)?
Thank you in advance.