LE does not support dual-boot and our installer will nuke anything else on the same target disk. Mint installer will be more flexible and should allow install into a specific partition, but if LE was installed first there isn't a spare partition so you may be nuking bits of LE when installing Mint, and Mint probably installs its own bootloader (overwriting ours) and either doesn't support making pretty menus that include existing other OS on the disk or it does a bad job of that.
The LE installer simply creates two partitions; one for boot files (SYSTEM/KERNEL and syslinux.conf) and one for a persistent storage area (/storage) and it installs the syslinux bootloader to the root of the disk. We are not dependent on syslinux; any bootloader will be fine, so it will be best to install Mint with a partition scheme that allows for LE being manually installed (copy boot files over) and with a manually created entry in the Mint-installed bootloader (they probably use grub).
TL/DR: there's a reason why we don't support or provide support on dual/mult-boot arrangements. Good luck 
Hi, the "LE does not support dual-boot" doesn't means it's impossible. The easy way probably is to install the LE to one drive, finish the setup, and install something else to the another drive. It's a good chance to the "second" OS to recognize the installed LE and to add to the own boot menu. Set in the bios the "second drive" as the boot disk. Could to work with a single drive, install the LE, finish the setup, boot from USB to a live linux, resize the LE "storage" partition (to make space for another OS), than try to use that free space for second installation. I never tried this (LE on RPi user), just an idea, if you ar ready to experiment a bit...
If you must have another OS installed, why not just install Kodi on that OS? I have multiple HTPCs running LE, but on my laptops, I just install Kodi, works very well.
