Important: I'm writing this when the last version of macOS (and the one I have installed) is Mojave. There is already a script which installs Mojave in a virtual machine here https://github.com/img2tab/okiomov. But if you are curios how to do everything manually to install High Sierra, then this guide may be useful.
After reading a few articles I ended up with these steps:
- On macOS, download the High Sierra installer (even if you have Mojave installed): https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
- If the High Sierra Installer starts, quit it.
- Open "Disk Utility".
- Click on "File" > "New Image" > "Blank image...". Or just press cmd+N.
- In the "Size" field, enter
13 GB
and save it wherever you want. - If the image is not mounted automatically, double-click the file you just created to do it.
- Open "Terminal"
- Run
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled
. If you changed the value of the "Name" field in the step where you changed the "Size", then instead of "Untitled" the image probably appears with that name you entered. - Once the previous command finished, continue with the following steps.
- Copy the file to some device which you can get access from Ubuntu (external drive or whatever works for you).
- On Ubuntu, open the "Terminal".
- Run
VBoxManage convertfromraw <path_to_input_.dmg_file> <path_to_output_.vdi_file>
. - Open "VirtualBox".
- Create a new machine of Type "Mac OS X" and Version "macOS 10.13 High Sierra (64-bit)" (probably others work, but I just tried with that one).
- Once the machine is created, go to the "Settings".
- Select "Storage" and click to add a hard disk. When asked click on "Choose existing disk" and select the .vdi file you created using
VBoxManage convertfromraw
. - Click "OK" and start the machine.
- Wait until you get to the screen where you have to choose the language. And choose your language.
- "macOS Utilities" appears. Select "Disk Utility" and click "Continue".
- Select the disk where you are going to install macOS (probably the same you created when creating the machine).
- Click "Erase".
- Verify that "Mac OS Extended (Journaled)" is the format selected and click "Erase".
- Once it finishes, Quit the "Disk Utility".
- Select "Install macOS" and click "Continue".
- Follow the instructions.
- Once it finishes, the machine automatically rebooted. What you have to do is power it off.
- Remove the installer hard disk from the machine. The one you added previously, not the one where you are installing macOS.
- Start the machine.
- You are going to see a screen where the last line is
Shell>
- Run
cd "macOS Install Data\Locked Files\Boot Files"
- Run
boot.efi
- Continue the installation normally.
References: