Category: macOS ISPW Firmware

Apple Silicon M1 Mac Recovery has changed! The interface, options and the way you reinstall macOS is all new. I will show you everything you need to know.

UPDATED 09/25/21

Apple Silicon Macs started to arrive in customers hands on Tuesday November 17th, 2020. One of the first things we need to understand is how to reinstall or factory erase macOS on Apple Silicon. All the old rules that you had to follow with Intel Macs has now changed. I will show you 3 different ways to reinstall macOS Big Sur on a Apple Silicon Mac.

If you are looking for more information on Apple Silicon Macs, I’ve wrote an article going over everything you need to know.

mrmacintosh.com/mac-transition-to-apple-silicon-everything-you-need-to-know-updated/

Internet Recovery is DEAD on Apple Silicon.

Right off the bat, we need to understand that Mac Internet Recovery on Apple Silicon is DEAD! Finally you don’t have to worry about IR errors and the problems that come with them.

Internet Recovery will still remain for Intel based Macs. For Apple Silicon we now have 4 different ways to reinstall macOS.

• 1. macOS Recovery = First line of recovery.
• 2. System Recovery = Hidden partition for when normal macOS recovery is not available.
• 3. macOS Big Sur USB Installer Drive. = Boot to a createinstallmedia based Big Sur full installer.
• 4. macOS System Restore via DFU mode + Apple Configurator 2.

Reinstall macOS on Apple Silicon Table of Contents

• 1. macOS Recovery
• 2. macOS System Recovery
• 3. Both macOS Recovery and System Recovery are not available?
• 4. macOS Big Sur USB Install Drive
• 5. How to Use Apple Configurator 2 to reinstall macOS on Apple Silicon
• 6. Apple Silicon Security Policy
• 7. Apple Silicon Compatible Versions of macOS
• 8. Can I downgrade macOS on Apple Silicon?
• 9. Where can I get macOS ISPW Firmware files?
• 10. Signed? What does that mean?

1. Apple Silicon macOS Recovery

Apple Silicon macOS Recovery is almost exactly the same as it is on Intel Based Macs. One of the major things that has changed is the way that you get into macOS Recovery. Instead of having to remember a bunch of keyboard commands you can now use the power button to get right to the boot picker macOS recovery menu!

https://youtu.be/lBiUSnrYyFM

The video above shows you how to factory restore / erase your Apple Silicon Mac and reinstall macOS.

2. Apple Silicon System Recovery

Apple Silicon System Recovery is a new hidden recovery option in addition to macOS Recovery. If for some reason macOS Recovery becomes corrupt, System recovery will load which is the same as macOS recovery. You can use it to reinstall macOS and macOS Recovery.

3. Both macOS Recovery and System Recovery are not available?

If something serious goes wrong with your Mac and it can’t boot into macOS you will see a new startup screen. (The blinking folder icon has been retired). You will now see a screen like this

This screen has a new Apple Support URL support.apple.com/mac/restore which will tell you that you need to restore macOS firmware via Apple Configurator 2 and a 2nd mac running 10.15.6 or newer. Restoration will now work the same on the Mac as it does on iOS iPhones and iPads.

4. Apple Silicon External Boot Options – USB Installer

On Apple Silicon external boot remains, but has changed.

External Boot for the macOS installer is now enabled by default

You no longer need to enter Security Options to enable External Boot!

Now you can build out an USB Installer of macOS Big Sur and boot your Apple Silicon Mac to it.

https://youtu.be/dQCp-rQlZuY

https://youtu.be/2iNDe2zAJyg

5. How to Use Apple Configurator 2 to reinstall macOS on Apple Silicon

If all options to reinstall macOS fail you can now use Apple Configurator 2.

• 1. Revive = Will restore macOS Recovery Only. (User data remains)
• 2. Restore = Will will download macOS and macOS recovery and reinstall them (THIS WILL ALSO ERASE YOUR HARD DRIVE)
• 3. Reinstall macOS = Reinstall macOS Recovery / System Recovery / macOS

This will help with rapid deployment in lab / school situations.

My Mac T2 BridgeOS Restore article will show you this process. It has not changed except for one thing. In the future the “RESTORE” option will automatically download the newest macOS ISPW file for you and install it. For now you will need to download it and and drag it over to the DFU icon.

I’ve also written an article that goes over the entire new DFU + Apple Configurator 2 Apple Silicon Restore process below.

Restore macOS Firmware on an Apple Silicon M1 Mac + Boot to DFU Mode

6. Apple Silicon Security Policy

New Apple Silicon Macs now have 2 Security modes.

1.Full Security = “iOS Security” – Only the latest signed version of macOS can be installed on an Apple Silicon Mac.

Full Security

Ensures that only your current OS, or signed operating system software currently trusted by Apple, can run. This mode requires a network connection at software installation time.

WWDC 2020

2. Reduced Security = Any version of macOS that was signed by Apple.

Reduced Security

Allows any version of signed operating system software ever trusted by Apple to run.

WWDC 2020

With the new Apple Silicon Security Policy, you can set a security policy for each container! On an Intel based Mac the security policy would be set on the entire system.

7. Apple Silicon Compatible Versions of macOS

Will you be able to install older versions of macOS? A quick review;

• Full Security = iOS based security, only the latest signed version of macOS can run on the system.
• Reduced Security = Any version of macOS that was signed by Apple can run on Apple Silicon
• Note: The shipping OS version will be the oldest OS available to install

8. Can I downgrade macOS on Apple Silicon?

Yes!

• Note. The “Shipping version” of macOS on Apple Silicon is the lowest OS that can be installed. An example of this is the M1 iMac which came with 11.3. You can not install Big Sur 11.2 on it.

9. Where can I get macOS ISPW Firmware files?

I started a new database page that will keep track of all macOS Apple Silicone IPSW Firmware files.

The article will include

• 1. Full ISPW Files from Apple
• 2. Date when released
• 3. Is the ISPW File still signed?
• 4. Size of the macOS ISPW download.
• 5. Build Version of the macOS ISPW file.

mrmacintosh.com/apple-silicon-m1-full-macos-restore-ipsw-firmware-files-database/

10. Signed? What does that mean?

Starting with Apple Silicon, macOS OTA (Over The Air) Firmware will be signed by Apple. This means that they control which version of macOS can be installed on your Mac. The difference this time around is that Apple gives us the option to turn Signed Checking OFF. So you will still be able to install older versions of macOS.

Apple Silicon macOS Reinstall