Hi, I was looking one night a few weeks ago about trying to modify Mac OS Sierra's InstallableMachines.plist in the installESD.dmg file. When I noticed it again this morning, I tried messing around with it again, but I still can't add anything. What I want to do is add a Mac Pro 2008 motherboard ID, which I got from browser.primatelabs.com but when I paste it in, it says the file is locked. So I click the unlock button, but it says that the file is on a read-only volume, despite the fact that when I right-click and get info, I have read/write privileges for the file. So I turned off SIP, thinking that that was the culprit, but I still can't edit the file. Then I copied it to my desktop and edited it from there, but when I drag it back into the installESD.dmg, it won't copy. I would like to get any info that people have on this subject.