Rolling back to prior OS on M2 chip mac

[roadkill401]

I bought an M2Pro mac mini last year that shipped with MacOS Ventura. it worked pretty well with some issues of attached drive disconnects but mostly worked fine. I bought the mac to make music primarily and for that side, stability is the key requirement. It ran into an issue where the T2 chip when into some panic mode and disassociated the internal drive so the Mac wouldn't boot. So I took it to an Apple Store and they said to fix it, they needed to reset the T2 and its Apple's policy that you MUST BE using the latest OS. So they reflashed the T2 and put me into MacOS 14 Sonoma. That ride hasn't been the smoothest with 14.5 totally messing up all the Plugins and causing iLok to just stop working.

I have tried with Apple to get a method to revert back to a prior MacOS version. This was a very simple thing with my old intel iMac. But it seems like Apple want to make the Mac like an iPhone in you can't simply reload an Old MacOS over a new one. It can't be a hardware limitation as I can install MacOS 13 Ventura onto an external attached drive and it works just fine. So it's not that the Firmware on the chip makes it unavailable.

Has anyone successfully rolled back an M chip Mac to a prior OS version (that the Mac chipset does support)? is there any instructions on how it pull this off? I have just ordered an M2 Macbook Air that I expect will ship to me with Ventura installed on it and I would really love to have both my Mac Mini and Macbook on the same MacOS where they can happily sit at for the next 10 years.

 

[Fishrrman]

I could be wrong, but I don't think that m-series Macs have a t2 chip.
Will others please jump in to correct if necessary?

Having said that...

Once you have the Macbook you might be able to use Apple Configurator 2 to put back the Mini to Ventura.
Some links:

Firmware and Recovery upgrades and downgrades on different Macs

What would happen to a Mac’s firmware if you installed Monterey beta to its internal or external disk? Could that be reversed?

eclecticlight.co

and

Revive or restore a Mac with Apple silicon using Apple Configurator

The only other way I can think of would be to:
1. BACK UP the Mini (I would recommend using either SuperDuper or CarbonCopyCloner, NOT time machine)
2. Create a bootable USB flash drive (I recommend using the free utility called "Mist" to download and create the flash drive in one integrated operation)
Get MIST here:

Release 0.10 · ninxsoft/Mist

Mist now ships logs to the unified logging system! You can view the Mist Log window via the: ⌘ + L keyboard shortcut Mist > Window app menu Show Mist Log toolbar button Logs can also be monitor...

github.com

(download the .dmg file)

3. Boot from the flashdrive
4. Open disk utility. Go to the View menu and select "show all devices" so you can see the Mini's SSD.
5. ERASE the SSD
6. Quit disk utility, open the OS installer, install Ventura
7. Migrate your stuff from the backup

This might be your best shot to "get back, get back, get back to where you once belonged".

 

[chrfr]

I bought an M2Pro mac mini last year that shipped with MacOS Ventura. it worked pretty well with some issues of attached drive disconnects but mostly worked fine. I bought the mac to make music primarily and for that side, stability is the key requirement. It ran into an issue where the T2 chip when into some panic mode and disassociated the internal drive so the Mac wouldn't boot.

Yes, you can downgrade. This is a data-destructive process. The fastest process is to use Apple Configurator and a second Mac to put the mini into DFU mode and restore the OS. Otherwise you could create a USB installer and start from that and reinstall Ventura that way.
And, no, Apple Silicon Macs do not have a T2 chip.

 

[roadkill401]

i can only base my inital posting on what Apple had said and the people at the Apple store in what information they told me. i can't vouch that the people at Apple know the total ins and outs of the systems. i know that there are lots of things that i know the mac can do that support say either is not possible or i didn't know it could do that. so it wouldnt surprise me if the Apple Silicon doesn't have a T2 chip inside it, but it might have a similar function inside the silicon chip itself that does what the T2 did with the intel based macs. it might be semantics

Now that i have some instructions that i can use is good. And as an added bonus, the mac mini is still under warranty so i guess if anything does go south with the downgrade then i still have the fall back to take it so Apple with the IT JUST STOPPED WORKING line. if they can make up stories for me, then sure as hell i can tell them anything with a clear conscience.

destructive downgrades are not a worry to me. i have more than one backup of all my data and all the programs i use i own and am sure they will install back without a problem, but i will contact any of the more questionable ones to make sure they don't get into a one install state and consider a wiped mac to be a new install.

thankyou to everyone who have responded. it is very helpful and just goes to show that the Apple community really does help each other out.

 

[Nermal]

so it wouldnt surprise me if the Apple Silicon doesn't have a T2 chip inside it, but it might have a similar function inside the silicon chip itself that does what the T2 did with the intel based macs. it might be semantics

Yep, the M2 is - more or less - a superset of the T2.

 

[Ben J.]

Create a bootable installer for macOS - Apple Support

You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system. These steps are primarily for system administrators and other experienced users who are familiar with entering commands in Terminal.

support.apple.com

I tried a couple of weeks with Sonoma on the mini in my signature, had no problems with Protools or ilok, but quite a few other things. Rolled back to Ventura with a bootable installer, really easy, and staying with ventura for now.

(Btw, I stopped trusting "service personell". These days they're more like shop assistants IMO.)

 

[Fishrrman]

Ben j wrote:
"Rolled back to Ventura with a bootable installer, really easy, and staying with ventura for now."

A question about the procedure.
I will assume that you first erased the drive with disk utility, is this correct?

IF so, a question about WHAT you erased:
- Did you erase the entire drive (including the secure system partition)?
or
- Did you erase "less" (and if less, what did you leave intact)?

Thanks...

 

[Ben J.]

Ben j wrote:
"Rolled back to Ventura with a bootable installer, really easy, and staying with ventura for now."

A question about the procedure.
I will assume that you first erased the drive with disk utility, is this correct?

IF so, a question about WHAT you erased:
- Did you erase the entire drive (including the secure system partition)?
or
- Did you erase "less" (and if less, what did you leave intact)?

Thanks...

To be honest, I actually don't remember exactly, but I'm pretty sure that if you just run the macOS installer from the bootable volume, it warns you that the target volume will be erased and all data lost. The apple guide to creating the usb installer that I linked to doesn't mention any erasing at all. I've done it a few times, and I have erased the whole container in DU also before installing. I'm not sure what difference it makes. The erase might affect the recovery partition with one method, and not with the other, not really sure.

 

[roadkill401]

The only other way I can think of would be to:
1. BACK UP the Mini (I would recommend using either SuperDuper or CarbonCopyCloner, NOT time machine)
2. Create a bootable USB flash drive (I recommend using the free utility called "Mist" to download and create the flash drive in one integrated operation)
Get MIST here:

Release 0.10 · ninxsoft/Mist

Mist now ships logs to the unified logging system! You can view the Mist Log window via the: ⌘ + L keyboard shortcut Mist > Window app menu Show Mist Log toolbar button Logs can also be monitor...

github.com

(download the .dmg file)

3. Boot from the flashdrive
4. Open disk utility. Go to the View menu and select "show all devices" so you can see the Mini's SSD.
5. ERASE the SSD
6. Quit disk utility, open the OS installer, install Ventura
7. Migrate your stuff from the backup

This might be your best shot to "get back, get back, get back to where you once belonged".

OK. I downloaded the mist app. now that is where I get lost. I can see in one tab the option to download all the firmwares. So I can select the right one and it creates an install macOS Ventura 13.4.1_xxxx.ipsw. I don't know what to do with that file so I just downloaded it. Then on the other tab you can select installed. but they are all from dated this year and all seem to be 13.6.x. but I want to install 13.4.1 version of Ventura. I can click on one of those and it will make a bootable usb but I don't think I have it right.

so I took the laptop to the Mac mini and plugged a thunderbolt 4 cable between the two. the Left Most plug on the laptop. I press and hold the power for ten seconds to turn off the MacBook. I press and release the power button to turn it back on. I hold the Power (L)control (L)option and (R)shift keys for 10 seconds. then release all but the power button that I hold for 3 more seconds. I am left with a MacBook that is powered off.

Well. went to a movie with the family and when I got back thought that I would give something else a try. It turns out that the documentation provided by Apple is wrong. it says it would work with a Thunderbolt 4 cable. I have plenty of them in 40gb/s mode and 40gb/s | 240w. Non of those work. but I did manage to find an old usb-c cable from my 2017 iPad Pro, and lo and behold that actually works. So then I am stuck in DFU mode without a clue on how to do the actual downgrade. Apple provides little to no documentation and will not provide any help over the phone insisting that the downgrade process is totally impossible. After a few curt words I did get a sr advisor on the phone who finally admitted to me that they just are not allowed to tell you how to do it over the phone.

If anyone else after me is stuck at this process. What you need to do is drag the new .ipsw file onto the DFU screen and that will allow you to either Restore the Boot Utility or Restore the firmware to the version dragged. What a technical nightmare.

 

[Fishrrman]

Re the reply 9 above.

I simply can't explain as to what you might be doing wrong.
I tried Mist to create a bootable USB flashdrive and it was "as easy as pie".

Hmmm... going to get out my MacBook Pro and retry the process right now.
PRINT OUT this reply (or you may not remember it)

OK, launched Mist.
Looking at opening screen.
DO NOT click on firmware. (up above)
DO click on installers.

BEFORE you go further, insert your flash drive so it's ready to select.
The flashdrive should be formatted to HFS+ (Mac OS extended with journaling enabled, GUID partition format). DO THIS NOW.
Name the disk "Untitled" (should be named by default).
Quit disk utility, you're done with it.

Now, look at the image below.

See the icon for creating a flash drive (look at the red arrow)?
CLICK IT.

Next, you will see this:

Go to popup menu and select the flashdrive (which we named Untitled, right?).

Then click "Select".

Now... just SIT BACK AND WAIT.
Mist should download the installer from Apple, then create the bootable flashdrive.
It will take a little while, so be patient. Figure 30-40 minutes. When done, you'll see checkmarks to the left of everything in the progress window, and the bootable flashdrive ought to appear on the desktop.

I can't make it any easier than this.

 

[roadkill401]

yes the part of making a bootable usb wasn't really my question or problem. I have made more than a few of them without the use of mist. I will agree whole heartedly that mist does do it with more grace and ease than the manual way. where i ran into the questions was the version numbers don't go back very far. I know that Apple did release some updates to Ventura recently that also has a terrible effect with many music plugins. I would need I guess to test multiple ones to see what does or does not work if going this way.

I did actually give making the USB a try first, and it did book wonderfully but the M2 mac wouldn't let me install ventura as it said that its not compatible or something to that effect. Its likely more to do with the Firmware and the hidden folder drive whatever.

For downgrading, I did get the DFU to work once I used the correct USB-C cable and not a ThunderBolt4 one. There apparently is quite a difference. The Mac is now running perfectly on 13.5 and I am back to creating music once again.