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As of Mint 18.3 the default is The [[Grub2 Bootloader]] or specifically grub-install (GRUB) 2.02~beta2-36ubuntu3.14+linuxmint1We installed Mint 19.2 first, and Mint 18.3 second. This caused the Mint 18.3 configuration to be the dominate configuration for the grub bootloader. Therefore, if we wish to change our grub2 settings we must boot to the Mint 18.3 operating system as making changes to the other would not take effect.The UEFI configuration can point to the grub2 configuration within /boot of one of the two linux partitions. The most recent linux to be installed with have the active grub2 configuration in the /boot of its own partition. The grub2 configuration if the former is completely ignored.In our example we installed 18.3 last, thus it has the active grub2 configuration. However, say we want to have 19.2 our primary Mint version and thus we want its grub2 configuration in its /boot to be the active one. To accomplish this do the following:# boot to the 19.2 (or whatever your original linux install was) # from terminal execute the following: apt-get install --reinstall grub-efi-amd64After you reboot you will be using the grub2 configuration of /boot from the partition with 19.2 and the boot menu will list 19.2 at the top.