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Don’t format a drive of M1 Macs from recovery mode

giuliomagnifico.medium.com

11–20 of 154 posts

Re: Don’t format a drive of M1 Macs from recovery mode

#11
Interesting. These are all the issues I will avoid from early adopters when I eventually get a newer Apple Silicon based Mac computer.

I have no time to go through the thorns and landmines over incompatible systems or buggy system software tools from Apple as described by the blog post.

Again, I will wait until the software on Apple Silicon is mature and the developer ecosystem catches up to it which by then I'll be getting an M2 or M3 based Mac.

Re: Don’t format a drive of M1 Macs from recovery mode

#12
post #3

Same, or similar behaviors with the 2020 Intel MBP. I ended up having to format the drive as an exFAT drive and then reformat again as APFS to get it to reinstall it was a real pain in the ass.

But at least with an intel Mac you can boot in target mode using cmd - t and then clone/mount/erase/whatever the disk from another Mac! Instead with ARM you can’t mount the disk as an external drive. That’s why this mess started!

A M1 Mac can be restored from Apple Configurator, the same as any other iPhone or iPad.

Re: Don’t format a drive of M1 Macs from recovery mode

#13
Big Sur appears to have introduced several new security features that complicate this process. I attempted a wipe on my 2019 16" Intel MBP to upgrade to Big Sur.... and after this, it required you to do something like sign in with a user to disable startup security, because it would not trust its own official Big Sur installer due to signatures maybe.

Re: Don’t format a drive of M1 Macs from recovery mode

#14
The easiest way to reinstall iOS Big SurmacOS on M1 Macs is to treat them as what they really are, glorified iOS devices, and DFU restore the operating system from another Mac with Apple Configurator or similar tools (macOS is downloaded as an .ipsw file and deployed on the M1 Mac). Works like a charm and is quite fast and guaranteed (barring bootrom/physical hacks) to ensure the device is not running non-Apple software.

P.S. T2 Macs are actually the most difficult to restore to the latest OS sometimes. The installer is anal about asking local password, booting from external USB, etc. and you might end up having to go through internet restore once and then upgrade the OS. M1 is actually an improvement and simplification from clean OS install perspective.

Re: Don’t format a drive of M1 Macs from recovery mode

#16
post #10

>Uff…what a paintful process! If an issue takes less than 5 different attempts to resolve and under 1-2 hours to fix, that can't really be called painful, merely annoying. Especially when it's only a one-time problem.

If your bar is "I want to do X, let's start by reading the Arch Wiki", then sure.

If your bar is "It just works", then for me at least, if it takes me more than 1 minute I'd describe it as painful. My mother would describe anything that's not immediately obvious as painful.

Re: Don’t format a drive of M1 Macs from recovery mode

#17
post #10

>Uff…what a paintful process! If an issue takes less than 5 different attempts to resolve and under 1-2 hours to fix, that can't really be called painful, merely annoying. Especially when it's only a one-time problem.

> No way I reinstall and do all the thing Apple suggests with another Mac with Apple Configurator.

When the resolution means that you need another Mac at hand it is not merely annoying if you don't.

Re: Don’t format a drive of M1 Macs from recovery mode

#18
post #10

>Uff…what a paintful process! If an issue takes less than 5 different attempts to resolve and under 1-2 hours to fix, that can't really be called painful, merely annoying. Especially when it's only a one-time problem.

Your threshold is probably way higher than the average Macbook user that probably does not even know about the recovery mode.

Re: Don’t format a drive of M1 Macs from recovery mode

#19
post #5

Why not just do the usual dd if=/dev/zero of= bs=1M count=1024 instead of using those weird proprietary tools?

This option is horrendously inefficient on most modern drives. For many SSDs, issuing a secure erase request is an almost instantaneous process as it only requires the drive to generate a replacement encryption key, and need not even entail bulk writing or erasing physical flash pages

Writing 1 GB of zeros is also almost instantaneous. Even though it's overkill, writing 1 GB is hardly worth worrying about. Though I'd recommend also wiping the backup GPT at the end of the drive.
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