Yes, put in wattOS! I am using Lubuntu 18.04 on imac 11,2 at work (I am typesetter at Bradford County Telegraph). I used the entire drive for Lubuntu. It works great! Be sure to put in some kind of fan control... You may have to disable ivp6 to get decent download speed or enable it in router. If you use wine, there are workarounds for that too. If you need a decent office program, I use FreeOffice 2018. There's more I can't think of right now.
