Had the same experience with my plastic MacBook from 2007 and I could install Fedora 27 and Mint using a related program to iso master. Good to know about ISO master.
Wrote about the process: “The 2007 plastic MacBook lives again with Mint-y Linux awesomeness” @harijay https://medium.com/@harijay/the-2007-plastic-macbook-lives-a...