How does recovery mode work on my M1 iMac?

Reading further from CCC - it appears the Full Installer of Big Sur needs to be pulled down and Installed to the External Drive to make it a Real Bootable Clone. Then - on the M1 and T2 Chip Intel - contend with About Startup Security Utility aspect to allow booing from External Dives.

Guess you have read all this from Apple ?? If so - sorry for posting.

Use macOS Recovery on a Mac with Apple silicon

howardfromlafayette wrote: "When I switched to my M1 iMac, I got a new cord, replacing the MicroB to USB-A cable with a MicroB to USB-C cable."

I think I can guess, but which of these two types do you have?...

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Last qstn: Is the cable connected to the Seagate via USB-A or USB-C?

Since Big Sur has a reputation for bugs and APFS works more efficiently with SSDs, I'm wondering if the problem is possibly related to the slowness of both your HD and cable connection (if USB-A).

On Catalina, my old HD connected via USB-A was bricked during a conversion to APFS by a backup app. So strange things can happen with Apple's new APFS on old, slow HDs.

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Reading over here at Carbon Copy Cloner regarding the Restore function as it relates to CCC. Find the Restore sort of has changed to Migrate from the CCC on external drive.

Have not attempting a Restore on an M1 based machine so thinking Restore is interchanged with Migrate while in Recovery Mode with TM Backup available ?

Will have to test this out sometime.

That’s probably it, but I haven’t attempted a restore. It doesn’t appear that Big Sur backs up the OS, but there is a “boot” folder in the Data volume backup. I wasn’t sure if that was some sort of compressed OS volume.

And, I don’t know if anything has changed since that CCC article.

That dialog seems to indicate the backup did not come from that Mac. No idea why, though.

If you try to restore a backup from another Mac, you have to install the OS and migrate from that backup.

Howard ~ The following may turn out to be irrelevant, but anyway...

Is your external TM drive an SSD or HD?

Did you format it as APFS or HFS+?

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howardfromlafayette wrote: "It is a 4TB Seagate disk APFS volume APFS (Case-sensitive), still mostly empty."

So is that Seagate an SSD or HD?

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