Awaiting SuperDuper for Big Sur
At present, it’s not possible to make bootable copies of Big Sur, even with
asr, Apple’s own built-in replication utility. As such, we haven’t released a Beta, or even an internal Alpha, because it wouldn’t meet our own requirements.[…]
In the meantime, my advice for macOS Betas remains as valid as ever: do not install a macOS Beta unless you have a critical business need to do so. These Betas, even when public, are not for general use, and certainly not for anyone who wants a reliable system for day-to-day work.
Time Machine is itself in beta, and it can’t make bootable backups. John Siracusa found that installing a Big Sur beta on a different drive made his Catalina volume inaccessible, presumably because the beta updated the BridgeOS firmware for his Mac’s T2.
Previously:
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I installed Big Sur on an external drive precisely to get the BridgeOS update. Without this, Mojave would spontaneously reboot every 2-3 days on my Mac Mini.
On the ATP episode I listened to John Siracusa’s problem was that a particular Big Sur beta apparently updated BridgeOS to a version that wouldn’t let his 2019 Mac Pro wake from sleep, even when booted into Catalina. He did a ton of work to figure out that was the reason for his wake from sleep problem and fixing it was a lot of effort. The ATP episode is a good listen.
@David Thanks for jogging my memory. Yes, it’s not as simple as what I wrote above. I think the start of the saga was that the BridgeOS update messed up sleep. And then I think he got locked out of the Catalina volume when trying to revive the BridgeOS, but eventually he figured out an undocumented solution to access the data and firmlink a new system volume to it. Anyway, the point is that in the era of BridgeOS we need to be careful of testing beta OS versions even when installing on a separate drive. And, of course, a beta OS can also affect data stored in your iCloud account.
I did not read this and tried to back up the Big Sur to a Catalina clone and wow what a mess. Bricked my internal hard drive on the MacBook Pro and could not get the clone to work.
Oh, I had another clone of the Catalina but it would not open on the MacBook Pro but would as an external.
Took my wife older MacBook running Catalina and was able to get to disk utility and finally erase the internal drive. Then restarted in system recovery. When I got done I opened up to ???Big Sur???
Been running fine since.
Hope we can get back with Superduper and wish I had read this first. Whats better than a clone? 2 Clones.
I came across an app similar to SuperDuper or CCC:
GET BACKUP PRO V. 3.6.2 which is totally compatible with Big Sur and
supplements Time Machine very usefully.
(I am not affiliated with Belight the company behind GBP)
It turns out that the Get Backup Pro clone is bootable after all. This was not apparent to me because my Mac was set to disallow external booting, and even after enabling that there is some sort of bug in Big Sur that makes the volume not show up in the Startup Disk pane of System Preferences. I can, however, select it if I hold down the Option key when powering on my Mac.
