Mac mini M4: macOS downgrade & external keyboard for startup

vnx273 wrote:

Hello everyone,

I’m currently using a Mac mini M4 running macOS 26, and I would like to downgrade it to macOS Sequoia 15.2.

Just curious why you want to go through the hassle to downgrade the OS? Especially to 15.2 when the latest update for Sequoia is 15.7.3.

If you are having specific issues with Tahoe, then explaining those issues and posting a complete EtreCheck report will allow us to assist you with any Tahoe related issues.

How to use the Add Text Feature When Posting an EtreCheck Report - Apple Community

I’d like to ask:

Is the downgrade process on a Mac mini M4 the same as on a MacBook (for example, using Recovery Mode or a bootable installer)?

With an M-series Mac, you need to create & use a bootable macOS USB installer to downgrade the OS.

Create a bootable installer for macOS - Apple Support

When booting into Recovery or selecting a startup disk on Mac mini M4, do I need to use an external keyboard, similar to how it’s required on some MacBook models?

An external keyboard is only needed if you are using a Desktop Mac, or your laptop's built-in keyboard is bad.

Otherwise using an external keyboard is up to you.

Any guidance or shared experience would be greatly appreciated.

Thank you very much!

Here is an Apple article for reinstalling macOS...you will need to use Disk Utility to erase the Volume Group since you want to downgrade the OS.

How to start up from macOS Recovery on an M-series Mac - Apple Support

When downgrading the OS you will need to restore from a backup made prior to the upgrade to Tahoe. You do not want to restore any Apple libraries from Tahoe to an earlier OS since those libraries may no longer be compatible with the older OS. For any other data, you will need to manually recover them to the downgraded OS from the backup.

Downgrading an OS can be a huge pain depending on how much your data has changed since you've done the upgrade. It is usually best to resolve any issues with the current OS.

If you don't have any backups, then you are in for a world of pain to downgrade the OS and you will definitely want to make sure you have at least two different good backups before attempting the downgrade.

Firmware Compatibility and Secure Enclave Risks

Be aware that upgrading to macOS 26 (Tahoe) likely includes a firmware update affecting the logic board and Secure Enclave Processor (SEP).

Downgrading to an earlier version (e.g., Sequoia) may or may not introduce firmware mismatch issues, leading to instability or loss of functionality.

Give up the idea of Downgrading to Sequoia 15.2 >> macOS 15.2 ( 24C101 )

That version was released Dec 11, 2024

The Oldest Version of Sequoia available from Apple is as per below

Finding available software

Software Update found the following full installers:

* Title: macOS Tahoe, Version: 26.2, Size: 16975578KiB, Build: 25C56, Deferred: NO

* Title: macOS Tahoe, Version: 26.1, Size: 16890687KiB, Build: 25B78, Deferred: NO

* Title: macOS Sequoia, Version: 15.7.3, Size: 15286709KiB, Build: 24G419, Deferred: NO

* Title: macOS Sequoia, Version: 15.7.2, Size: 15285166KiB, Build: 24G325, Deferred: NO