Workaround for Macinabox boot loop on Unraid server 6.9.2 (82ghost82)

Rough guide to update scripts and opencore.img

Big thanks to 82ghost82 for the workaround and PR! And of course SpaceinvaderOne! Here are the steps I took to get Macinabox VM working on my Unraid server based on the the above pull request from 82ghost82. Note: this worked for me (August 2021) but may change.