Downloading macOS IPSW files for use with Mac virtual machines on Apple Silicon Macs

A change between creating Mac virtual machines on Intel Macs and creating them on Apple Silicon Macs is that virtualization on Apple Silicon Macs often assumes that the virtual machine is built using a macOS restore image . These restore images are files with an .ipsw file extension and are commonly referred to as IPSW files.

Apple publishes the download links for macOS restore images via the following URL:

https://mesu.apple.com/assets/macos/com_apple_macOSIPSW/com_apple_macOSIPSW.xml

If you look at the XML file from the link above, it provides download links for the current version of macOS for the various Mac models which support running that version of macOS.

Among the various models listed is the model identifier for Mac virtual machines (VirtualMac2,1) created using Apple’s Virtualization framework. This means that we should be able to identify and download the appropriate IPSW file for use when building Mac virtual machines.

Using this information, I’ve written a script to download the appropriate IPSW file for building macOS virtual machines by checking the file linked above for the download URL associated with the VirtualMac2,1 Mac model. For more details, please see below the jump.

create_macos_vm_install_dmg updated for macOS Big Sur installer disk images

As part of testing macOS Big Sur 11.0.0, I’ve updated my create_macos_vm_install_dmg script. For more details, please see below the jump.

Using bootstrappr to build testing VMs with VMware Fusion

As part of my preparation for next week’s WWDC conference, I’ve been working on ways to build virtual machines using VMware Fusion for testing. In previous years, I have used NetBoot-based solutions to help me with this process. With NetBoot going away though, I’ve started using bootstrappr as my replacement deployment tool.

Bootstrappr is designed to install packages and scripts, but in my case I’m having it install only one package: a firstboot package created by First Boot Package Install Generator.app. The firstboot package in turn installs a set of installer packages to configure the VM and install the software I want. For more details, please see below the jump.

Mouse doesn’t move at FileVault login screen in VMware Fusion macOS Mojave VMs

As part of working with FileVault on macOS Mojave, I’ve been using VMs running in VMware Fusion 11.x for testing. As part of that, I’ve seen a problem where the mouse doesn’t move when the VM has booted to the FileVault login screen. The keyboard responds and arrow keys can be used to select users, but the mouse itself is immovable and does not respond.

After some research, I ran across someone who had the same issue and found a workaround. For more details, please see below the jump.

Building macOS installer disk images for virtual machines with create_macos_vm_install_dmg

A while back, I wrote a couple of scripts which built installers for Mac virtual machines:

• create_os_x_vm_install_dmg
• create_macos_vm_install_dmg

However, Apple made some changes to the macOS installer starting in macOS Sierra 10.12.4 which broke the method I was using to build the installers. Recently though, I figured out that I could use Apple’s createinstallmedia tool to help me with building installers for Mac virtual machines again. After a substantial re-write, create_macos_vm_install_dmg is able to create bootable disk images for virtual machines running macOS Sierra, High Sierra and Mojave.

One change from the previous version of the create_macos_vm_install_dmg script is that the resulting installer no longer runs an automated installation. Instead, it will be necessary to follow the prompts to select the language and drive to install the OS onto. For more details, please see below the jump.

Setting your Mac to receive macOS beta updates using seedutil

As part of a discussion of how to build test VMs, a colleague mentioned how they were using the seedutil tool to help configure Macs to access Apple’s beta updates. I hadn’t run across this tool before, so I decided to do some research and see if I could make it work for my own testing needs. For more details, see below the jump.

Resizing a macOS VM’s APFS boot drive to use all available disk space

A while back, I wrote a post on how to resize the boot drive of an existing virtual machine. However, that guidance only applies to a boot drive that uses HFS+ for its filesystem.

Now that Apple File System (APFS) is available and the default file system on macOS High Sierra, a different procedure must be used in order to resize the APFS-formatted boot drive of an existing virtual machine. For more details, see below the jump.

VMware Fusion 8.5.8 adds Apple File System (APFS) support

VMware recently released VMware Fusion 8.5.8, which according to the release notes includes the following:

Another improvement which is not mentioned in the release notes is that VMware Fusion now includes support for the following:

• Using the macOS High Sierra beta installer as a valid installation source
• Booting macOS VMs from Apple File System (APFS) formatted drives.

For more details, see below the jump.

Creating macOS installer disk images for VMware Fusion and ESXi with create_macos_vm_install_dmg

I’ve had a tool available for a while named create_vmware_osx_install_dmg, but it looks like it has reached the end of the road with macOS 10.12.3. The reason for this is because macOS 10.12.4 has introduced a change that prevents the addition of third-party packages to the OS installer. create_vmware_osx_install_dmg uses the addition of a third-party installer package, so unfortunately this tool cannot be used to generate 10.12.4 or later OS installers.

That said, I still want to be able to create macOS installer disk images for VMware Fusion and ESXi, so I’ve forked create_vmware_osx_install_dmg into a new script named create_macos_vm_install_dmg. create_macos_vm_install_dmg will generate stock OS installer disk images for the following OS versions:

• Mac OS X 10.7.x
• OS X 10.8.x
• OS X 10.9.x
• OS X 10.10.x
• OS X 10.11.x
• OS X 10.12.x

This script does not use a third-party package, so it is able to build a macOS 10.12.4 installer disk image. For more details, see below the jump.

Resizing a virtual machine’s boot drive to use all available space

Every so often, it’s necessary to resize the boot drive of an existing virtual machine. The process of resizing the VM’s boot disk from outside the VM is usually pretty straightforward:

1. Shut down the VM
2. Go into the VM’s drive settings

3. Resize it to the desired size

4. Power on the VM.

However, when the VM boots up, the disk space used by the OS won’t have changed.

However, the OS can detect that there is available unallocated disk space that it isn’t using.

Fortunately, this is a correctable condition and the fix can be applied without needing to shut down the VM or boot from another drive. For more details, see below the jump.