To fix that we need to get a read-write (sparse image format) copy of the image: hdiutil convert ElCapitan-base.dmg -format UDSP -o ElCapitan.sparseimage At the moment, though, that’s missing the copy of OS X that it actually needs to go and install into your VM. Okay, so that’s built us a read-only (DMG format) bootable image for the installer.
Now we want to use that iesd tool to build a bootable image from the installer we downloaded from the App Store: iesd -i /Applications/Install\ OS\ X\ 10.11\ Developer\ Beta.app -o ElCapitan-base.dmg -t BaseSystem (Warning: you’ll need at least 15GB of disk space free to deal with this next section safely… more if you don’t clean up the two temporary images we build along the way)įirst up we want to install the iesd Rubygem which provides a nice way to deal with Apple’s InstallESD.dmg files: sudo gem install iesd
This section is all command-line stuff, so go fire up Terminal.app.
So let’s take a look at those, one by one… Step 1: Download El Capitan from the App StoreĬurrently you need to be a registered developer. Provided you are, you can download the beta from Apple’s website (this redeems a coupon inside the App Store, so you need to be on a Mac to start the download). Essentially there are 4 main things we need to do:
