[mschmitt]

I've been trying to create a bootable clone from a 2023 MacBook Pro (M2 Pro chip), and failing. I'm wondering if these data points track with other's experiences.

I set up the MBP by using the Migration Assistant to copy from the old MacBook Pro, i.e. I didn't use SuperDuper!. Then I tried to create the clone, using the same 1TB HDD partition that I was using before:

1. Used SD erase-then-copy to clone the Ventura 13.5.2 system volume and the data volume to the HDD, i.e. via asr.
2. Tried to boot. It failed early on with a kernel panic: Library /usr/lib/libSystem.B.dylib not loaded
3. Tried everything I could think of to boot: ran First Aid, Safe mode, re-cloned, different USB adapter, different port, USB 2.0 cable, etc. All attempts ended the same.
4. To rule out the hardware, I used the full Ventura 13.5.2 installer to install onto the backup drive, overlaying what was there before (i.e. not an erase first). And then...
5. That booted with no errors! So it isn't the hardware! There's something different in what asr did?
6. But, I couldn't turn on FileVault; clicking the "Turn On" button had no effect. I think this was because for some reason, my userid didn't have a Secure Token (it was reading as "DISABLED").
7. I thought, better make sure I can boot a second time. Surely if it worked the first time it would work again. But just to make sure...
8. Nope, can't boot it again. Now it gets to the login prompt, but after that, panics with a resource busy error: "registry root held busy".

So there's at least three problems going on with cloning from Apple Silicon (or Ventura?) to an external HDD:

• asr did not produce a bootable drive
• Installing Ventura on top of the drive created by asr made it bootable, but without the secure token associated with my userid. (I think it may have created a new id with the secure token, but haven't confirmed that.)
• Can't boot after the initial boot.

And I see some clues that the last problem is really due to an assumption in the boot code that if you're on Apple Silicon, then you must be on a SDD, and therefore it doesn't need to adjust timeouts to allow for a slower HDD. So, it appears that it is timing out in the code that is waiting for extensions to load.

While it is true that the internal drive on Apple Silicon will always be a SDD, the websites I've consulted said that Apple Silicon Macs can still boot from HDD. Now I'm thinking that's only if you're lucky and your HDD is fast enough that you don't get caught by the timeouts.