What is the safest way to downgrade to Big Sur 11.0?

[Sovon Halder]

I'm using a mac mini M1 and currently on 11.3.1. I'd like to go back to the stock version that came installed with my mac.
If there is a definitive guide or instructions, please let me know so I can follow that.

 

[Mr_Brightside_@]

How to reinstall macOS - Apple Support (CA)

You can use macOS Recovery, your computer's built-in recovery system, to reinstall the Mac operating system. Reinstalling macOS doesn't remove your personal data.

support.apple.com

Other macOS installation options​

When you install macOS from Recovery, you get the current version of the most recently installed macOS, with some exceptions:

• On an Intel-based Mac: If you use Shift-Option-Command-R during startup, you're offered the macOS that came with your Mac, or the closest version still available. If you use Option-Command-R during startup, in most cases you're offered the latest macOS that is compatible with your Mac. Otherwise you're offered the macOS that came with your Mac, or the closest version still available.
• If the Mac logic board was just replaced, you may be offered only the latest macOS that is compatible with your Mac. If you just erased your entire startup disk, you may be offered only the macOS that came with your Mac, or the closest version still available.

 

[Sovon Halder]

I use the 2020 M1 mac mini. I have an image of an earlier big sur but I can't tell from that dmg file what version of big sur it is.I can use an external usb installation drive and completely format/erase the system. I want to go back to the stock version, if possible.

 

[Sovon Halder]

I'm. getting this error "this copy of macos Big sur is too old to be opened in this version of macos". I even erased the apple. sdd from recovery menu but still can't boot from the external thumb drive.

Any solution to this?

 

[Joeronzk]

It seems the big sur version external usb drive is too old, like Beta. You need to download latest macOS Big Sur (11.1.3) from Mac App Store and use createinstallmedia command to recreate a bootable usb for installation.

 

[Sovon Halder]

It seems the big sur version external usb drive is too old, like Beta. You need to download latest macOS Big Sur (11.1.3) from Mac App Store and use createinstallmedia command to recreate a bootable usb for installation.

Latest is 11.3.1 right? not 11.1.3!?

Also I want to go back to the stock old version instead of a fresh install of the latest version.

 

[Sovon Halder]

Just leaving it here for anyone else who might be curious about this. After much efforts I was still unable to boot from my thumb drive because it said the OS was too old even though my mac mini came with 11.0.1 and I was trying to install 11.0.1 & 11.1 (both failed). Turns out there is no way to go past a certain version.

So I used the tutorial of MrMackintosh:https://mrmacintosh.com/category/downgrade-macos/ and downloaded the oldest one I could find. At the moment of this writing it's 11.2.1 (20D74 App:16.4.06), the one for which apple download link is still available. The installation went pretty smooth after I booted from it.

One small note though: It's a good idea to try to run the image on your existing mac before you make a bootable usb and erase your SSD for fresh install. If you don't receive the "too old can't run" from the dmg, you won't receive the error on the recovery window. So you're good to go. Would save you hours.

 

[Joeronzk]

Latest is 11.3.1 right? not 11.1.3!?

Also I want to go back to the stock old version instead of a fresh install of the latest version.

Sorry, it is typo. The latest one is 11.1.3.

 

[Apple_Robert]

Just leaving it here for anyone else who might be curious about this. After much efforts I was still unable to boot from my thumb drive because it said the OS was too old even though my mac mini came with 11.0.1 and I was trying to install 11.0.1 & 11.1 (both failed). Turns out there is no way to go past a certain version.

So I used the tutorial of MrMackintosh:https://mrmacintosh.com/category/downgrade-macos/ and downloaded the oldest one I could find. At the moment of this writing it's 11.2.1 (20D74 App:16.4.06), the one for which apple download link is still available. The installation went pretty smooth after I booted from it.

View attachment 1780839

One small note though: It's a good idea to try to run the image on your existing mac before you make a bootable usb and erase your SSD for fresh install. If you don't receive the "too old can't run" from the dmg, you won't receive the error on the recovery window. So you're good to go. Would save you hours.

USB installers don't last long before they expire. The same goes for OS downloads. That is why you got the message you did.

 

[Sovon Halder]

USB installers don't last long before they expire. The same goes for OS downloads. That is why you got the message you did.

I'm surprised to say the least. I thought unlike iOS, in mac we have the freedom to jump between different OS versions as we like. I once downgraded my 13" 2017 macboook pro from Mojave to Sierra - that was jump between 3 distinct editions of the OS - and it went fine. But now I tried to jump between incremental updates within the same OS and it didn't work.

Anyways it's for the better I think. Until 11.2 there was bluetooth issue and connection was choppy all the time, my mouse used to drop connection 3 times a day. It's okay that I have 11.2.1 now. Anything after that has been security updates and whatnot, no major broken thing fix for mac mini.

Now I need to figure out how I can absolutely stop this machine from getting OS updates from Apple.

 

[patearrings]

Shift-Option-Command-R on boot will offer you the installation of macos that came with your mac.

EDIT: Just seen you are on M1, not sure if it works for m1.

 

[Sovon Halder]

It doesn't.

 

[allan.nyholm]

@Sovon Halder if I'm getting this right you have an old dmg file with a supposed 11.0 Big Sur on it, but you are unable to verify if it's actually 11.0 from the DMG?

If you currently have a working Big Sur installation; can you mount the DMG and inspect the DMG with what ever it contains with a application such as the Pacifist program from charlessoft.com
or the unpkg program https://www.timdoug.com/unpkg/
You might have to go a little deep inside the osinstall.pkg inside the DMG (if your DMG contains such a file) There's sure to be a version.plist or info.plist file somewhere there that indicate the version of Big Sur you have inside that DMG file.

If you set back your clock in Terminal inside Recovery on your M1 Mac mini to a time where Big Sur 11.0 was released - would that work? Currently I forget the correct syntax, but probably something like "set date" or"set date time" and then some date in a syntax that includes year and month + day. The internet should provide you with a search result better than what I can give right off the bat here with one foot out the door

If your DMG contains an Install Big Sur.app then a Get Info on the .app should suffice for checking the version. Or inspect the .app for a version.plist as mentioned above.

 

[Sovon Halder]

No I'm all set, all good here.

To the topic of finding out the macos version from the dmg file - https://apple.stackexchange.com/questions/252940/how-to-identify-build-number-of-a-macos-installer