Monday, September 7, 2020 [Tweets] [Favorites]

Awaiting SuperDuper for Big Sur

Dave Nanian:

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.



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.

David Gelphman

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.

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