This App Can Download Any Version of macOS
Whether you're setting up a virtual machine for testing or attempting to restore macOS on a device that won't boot, sometimes you need to download a specific version of the Mac operating system. The problem: Apple doesn't make this particularly easy to do directly.
A free program called Mist, by developer [Nindi Gill](Nindi Gill), can help. Using it, you can download any version of macOS, or at least as far back as Lion (which debuted in 2010). More than that, you can obtain these operating systems in many formats.
Mist can deliver an older OS in multiple formats
Mist can generate an Application Bundle (.app), a Disk Image (.dmg), or a Bootable Disk Image (.iso) for any operating system version. Any newer than macOS Big Sur (from 2020) will work with both Intel and Apple Silicon Macs; older versions of macOS only work on Intel devices. Mist can also download a Firmware Restore file (.ipsw), which can be used only with Apple Silicon devices. The software can also turn any USB drive into a recovery disk.
Mist packs a lot of power, is what I'm saying, and that can make the application a little overwhelming when you first start it up. There are two main tabs: Firmwares, which offers the Apple Silicon-only .ipsw files for newer Macs, and Installers, which offer the other formats I noted above, alongside the ability to make a USB recovery disk.
Choose the format you want, then select the operating system you want. Note that when you first open the application there will be operating systems offered that are not compatible with your Mac. You can hide these by clicking the Only show compatible versions box at the bottom of the window. Optionally, you can also enable beta versions of macOS.
If you're downloading a firmware, you just need to click the download button and you'll soon have the IPWS file you need to restore a device.
If you're downloading an installer, you can choose which format you want after clicking the download button.
Use Mist to turn any USB into a recovery disc for your Mac
Finally, to create a USB recovery disc using Mist, click the hard drive button within the app. Note that only Big Sur and later versions are supported, and that doing this will delete everything that's currently on the USB drive. The tool will download the operating system and reformat the drive for you, though, so that's nice. When I've made such disks in the past, it required multiple tools, so it's nice to have everything taken care of in one step.
The bottom line
Mist isn't for all Mac users, but it's the sort of thing anyone who repairs Macs regularly should probably have around, and it's also great if you are the sort of person who uses virtual machines a lot. I'm glad I learned about it on App Addict. It's pretty cool.