Is Big Sur 11.1 a Universal Binary in itself?

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Is Big Sur 11.1 a Universal Binary in itself?

I have an Intel and a new M1 Mac Mini. I want to use an external clone of the Intel Mini as a BOOT drive on the M1 Mini. Thus allowing me to begin testing all my applications on the M1 silicon.

I made a spare fill backup of my Intel Mini using Carbon Copy Cloner to and external drive.

I then upgraded my Intel Mini to Big Sur 11.1 and spent a while testing. All works fine.

I then used CCC to make another external clone of the Big Sur 11.1 but the M1 Mini refuses to let me boot from it. I have already used Recovery Mode to allow booting from external drives.

When I use Startup Disk I can pick the external. When I click Restart I am asked am I sure and I enter my admin password. After a few seconds "Unable to set startup disk" dialog appears with "SDErrorDomain error 104"

Bottom line question: is it possible to create a universal Big Sur external boot drive that works on all Big Sur compatible Intel and M1 macs?

Edit: and I know Rosetta 2 will help me with older software for years to come but I still want to make a universal boot Big Sur.

thank you

qb

Posted on Dec 16, 2020 6:20 AM

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Answer 1

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leroydouglas

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Dec 16, 2020 7:14 AM in response to qbpals

qbpals wrote:

I then used CCC to make another external clone of the Big Sur 11.1 but the M1 Mini refuses to let me boot from it. I have already used Recovery Mode to allow booting from external drives.

Per the developer's website— M1 clones are not bootable at this time, however still a viable backup of the M1 Big Sur...

The system now resides on a "Signed System Volume." This volume is cryptographically sealed, and that seal can only be applied by Apple; ordinary copies of the System volume are non-bootable without Apple's seal. To create a functional copy of the macOS 11 System volume, we have to use an Apple tool to copy the system, or install macOS onto the backup.

ref: https://bombich.com/blog

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Answer 2

qbpals Author

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Dec 16, 2020 7:27 AM in response to leroydouglas

Wow! Thank you leroydouglas - this was extremely helpful. And as always Bombich software is just great. I'll standby and see what the future of Big Sur provided. I do see the blog about BS and M1 bootablity is from before 11.1. However as I cannot get an external 11.1 to boot my M1 Mini that the issues is likely still the reason. thank you again.

qb

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Answer 3

Dec 16, 2020 6:56 AM in response to qbpals

An Intel install of Big Sur on an external drive will not

work because it is not compiled for M1 chip.

While the installer may be universal, the installed code itself

is not.

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Answer 4

qbpals Author

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Dec 16, 2020 7:30 AM in response to qbpals

Oh I guess my question of "universal binary Big Sur" for booting M1 and Intel cannot be answered until M1s can be externally booted.

qb

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Is Big Sur 11.1 a Universal Binary in itself?

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