Trying to boot big Sur SSD on mini m1

[Hsjsksha]

Currently using iMac 27 2014 with USB Samsung t7 with big sur installed, however I'm having problems to boot the drive on iMac mini m1 on either usbC Or UsbA, I was holding power button and wait for the boot screen showing the selection of the boot drive, it doesn't boot at all after clicking on the ssd drive.


But it works fine on iMac 2014, advise please

 

[MarkC426]

I am not sure if you can boot an AS Mac with an Intel Mac boot disk…..
If you can you would need to change the T2 settings to allow any boot disk.

What is the Startup Security Utility on Mac?

Use Startup Security Utility to ensure a Mac with an Apple T2 Security Chip starts up from the designated startup disk and a trusted operating system.

support.apple.com

 

[Hsjsksha]

I am not sure if you can boot an AS Mac with an Intel Mac boot disk…..
If you can you would need to change the T2 settings to allow any boot disk.

What is the Startup Security Utility on Mac?

Use Startup Security Utility to ensure a Mac with an Apple T2 Security Chip starts up from the designated startup disk and a trusted operating system.

support.apple.com

How to change t2 setting ? M1 does support big Sur so should work. But it just doesn’t boot for some reason

 

[DeltaMac]

Look at the link that MarkC426 posted.
You have to change the boot settings in the Startup Security utility, which will allow booting from external drives.
Without that, you can't boot from any external drive.

 

[Mike Boreham]

Currently using iMac 27 2014 with USB Samsung t7 with big sur installed, however I'm having problems to boot the drive on iMac mini m1 on either usbC Or UsbA, I was holding power button and wait for the boot screen showing the selection of the boot drive, it doesn't boot at all after clicking on the ssd drive.


But it works fine on iMac 2014, advise please

You can’t boot a Silicon mac from an external with Intel macOS installed. You will have to create a new install on the external. You do not need reduced Startup Security to do this on Silicon Macs.

 

[Hsjsksha]

New install on external? How do I have my old data to the m1?

 

[Mike Boreham]

New install on external? How do I have my old data to the m1?

Migration Assistant or Setup Assistant.

 

[Fishrrman]

I don't think this can work.

A boot drive created on an Intel Mac won't boot an Apple Silicon Mac.
Even if it's "the same version of the OS".
The necessary OS resources "arent' there".

Other possible problems:
If the external drive is a platter-based hard drive, Apple Silicon Macs may not boot, either -- the drive is simply too slow to handle it.
An SSD is pretty much required.

If you want an external boot drive for an Apple Silicon Mac, what you need to do is:
1. Start with a blank external SSD, connected to the AS Mac
2. Format it to APFS, GUID partition format (with disk utility)
3. Now boot to recovery on the AS Mac
4. MAKE SURE system integrity protection is disabled, and also disable all "startup security".
5. Choose to "re-install" the OS, but when the installer asks WHERE you want to install, install onto the EXTERNAL SSD.
6. When the install is done, you should be booted to the new install
7. Now connect a backup (or external boot drive) from the OLD iMac
8. When setup assistant asks if you want to migrate, YES, you do
9. Point the way "to" the backup drive
10. Give setup assistant time to digest things.
11. Select what you want to migrate and let SA do the job.
12. When done, you should have a bootable AS-based drive with your "old stuff" on it.

Yes, it's "a long process".
But I don't believe there's any other way.