Don’t format a drive of M1 Macs from recovery mode • Hacker News Board

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

#81

Post by m1mac » Thu, Feb 18, 2021, 12:33 PM UTC

I agree that disk management of M1 Macs is poorly documented, but the author's issue appears to stem from:

> Nope, this don’t work as I suspected… so, let’s check online, Apple suggests a long procedure and a short by typing “resetpassword” in terminal, that was a chance but since it founds no users, there’s no passwords to reset.

"resetpassword" opens Recovery Assistant. Recovery Assistant is primarily intended to provide a "forgot password" flow, which is why it wants to identify a user. However, in the app menu bar, there is an option called "Erase Mac." That is how you do a full secure erase of an M1 Mac. It will work without any user, and even without any OS install at all. (I have tested this myself by erasing a machine multiple times without reinstalling the OS.)

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

#82

Post by southerntofu » Thu, Feb 18, 2021, 12:39 PM UTC

superhuzza wrote: post #62

elcomet wrote: post #60

Earlier quoted context omitted.

Why though ? If someone wants to harm you, they can damage the hard drive enough so that the data is unreadable if they have physical access.

So that they can use/sell the stolen Macbook, which is much more common than stealing a Macbook to delete the data.

What's wrong with using stolen hardware? I mean we could argue stealing is wrong, in which case we'd have to take a look at why people are stealing and from whom (partitioning of wealth) so we can find solutions.

If we're not looking at the root of the problem, then we're just complicating legitimate use cases. Preventing theft is only the official argument, but it doesn't stand any form of scrutiny: as long as there's inequality (i.e. incentives to expropriate people who have too much, to serve people who have too little) there will be theft.

The truth behind iCloud lock is Apple has been involved in mafia-style dealings with national mobile phone operators (which involved promises/contracts to sell millions of units), inundating the market with operator-sponsored iPhones, and they really don't want a second-hand market at all because they are a luxury brand.

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

#83

Post by m1mac » Thu, Feb 18, 2021, 12:42 PM UTC

marcan_42 wrote: post #54

M1 Macs are not like Intel macs, Apple have done a dismal job of documenting them, and their "for users" tooling is still buggy and broken because the launch was clearly rushed. Here is what you need to know to actually understand these things: The SSD has 3 partitions. Each partition is an APFS container. Each container contains multiple APFS volumes. Your OS, and everything you care about, is on the second partitio…

> Additionally, the SEP data is stored separately from the OS (in one of the volumes of the first container). To wipe that, after wiping the partition and before reinstalling, run `xartutil --erase-all`.

I believe the "Erase Mac" function in Recovery Assistant also erases the SEP data, based on the output of `xartutil --list` before and after. If I'm correct about that, going through Recovery Assistant should be the recommended way to fully erase an M1 Mac (short of a DFU restore through Apple Configurator which also restores firmware).

On T2 Macs, `xartutil --erase-all` would wipe all SEP data, including the encryption keys used for the drive. In other words, it was the equivalent of a secure erase and was my recommended way to fully erase a Mac before resale. I suspect Recovery Assistant is just doing the equivalent of `xartutil --erase-all`, but I haven't tried `xartutil --erase-all` on an M1 because I'm afraid to brick the machine to the point of needing a DFU restore, and I don't have another Mac at hand to run Apple Configurator with right now.

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

#84

Post by matwood » Thu, Feb 18, 2021, 12:45 PM UTC

PurpleFoxy wrote: post #43

digi59404 wrote: post #25

This is because the author didn't delete the entire volume group. You have to delete the whole volume group, i.e. erase the entire drive and it's partitions to reinstall OSX. This isn't new with the M1 Macs. This has been a thing since they introduced APFS. When they went into disk utility after the cli - Then they could delete everything and kick off the OSX Install. If the APFS Volume Group still exists the install…

I was kind of shocked at how hard it is to factory reset a MacBook. I had one at work and I had to pass it on and the guide is a multi step process which I messed up the first time and ended up reinstalling with my user account still there. Had to start again which takes hours. Why does the recovery not just have a button called factory reset which unlinks your apple account, deletes the volume and then sets it all u…

Because of the anti-theft feature of Find My, there are steps but they are pretty straight forward.

https://support.apple.com/en-us/HT201065

I've found the process is fast if you have a good internet connection to download macOS again. Otherwise, that's where it seems a lot of the time goes.

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

#85

Post by matwood » Thu, Feb 18, 2021, 12:50 PM UTC

Jonnax wrote: post #28

liminalsunset wrote: post #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.

I think the reasoning is that it's to prevent a stolen laptop from being stolen, wiped and resold without the owner allowing it through their credentials. I remember a poster on HN saying that after some exploit for the T2 security chip came out, they were making money from being paid by thieves to use the exploit to wipe the devices. Of course they said they don't ask any questions which as we all know is an iron cl…

Yeah, the high resale value of iPhones and Macs make them prime theft targets. Locking them to a user makes them less desirable to steal.

IIRC iPods were similar. Early on, people wearing white headphones were targeted by thieves.

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

#86

Post by m1mac » Thu, Feb 18, 2021, 1:08 PM UTC

wtallis wrote: post #31

rvz wrote: post #22

Earlier quoted context omitted.

You do realise if you get this wrong, you can't simply 'replace' the SSD on an Apple Silicon based Mac? You'll likely brick the device if the recovery partition is also wiped in the process. It's back to the Apple Store for you.

For years, Intel Macs have been able to net boot to install the OS onto an empty drive. Did Apple ditch that functionality or move it from the firmware to a recovery partition with the M1 Macs?

From what I can tell, Internet Recovery (which downloaded a recovery OS) is gone and replaced by 1TR which is stored on a hidden flash partition. 1TR is capable of downloading the OS and installing it, so in a way it can be considered the replacement for Internet Recovery.

While architecturally simpler (and probably more secure by allowing the network stack to be removed from the low-level boot infrastructure?), the disadvantage is that you can mess up the 1TR partition. If you do, the only way to recover the machine is to do a DFU restore from another Mac via Apple Configurator. That's not terribly convenient if you don't have another Mac around. (An Apple Store can DFU restore for you, but last I checked Apple Stores are appointment-only due to COVID and it's almost impossible to get an appointment there these days.)

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

#87

Post by lupire » Thu, Feb 18, 2021, 1:27 PM UTC

southerntofu wrote: post #80

PurpleFoxy wrote: post #76

Earlier quoted context omitted.

It should just ask for your Apple ID password when you do the reset. It’s not that hard. Honestly it should even be an option within the main OS

Why, though? Physical access to the hardware should prevent you from accessing existing files (encryption at rest) but should not prevent you from resetting/reusing the device. Does your fridge come with FridgeID? Or a book? Introducing such mechanisms is really hostile to users, especially poorer users of second-hand hardware who have to go through extra (shady) hoops to get a device running just because some rich S…

Who is going to walk a away with my fridge? How about my car? Many users appreciate having anti-theft protections on their easy to physically-access devices, and very few need to wipe of the owner's account.

It's great that you have a niche use case, but that doesn't make your case the priority over the main use cases.

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

#88

Post by m1mac » Thu, Feb 18, 2021, 1:33 PM UTC

marcan_42 wrote: post #54

M1 Macs are not like Intel macs, Apple have done a dismal job of documenting them, and their "for users" tooling is still buggy and broken because the launch was clearly rushed. Here is what you need to know to actually understand these things: The SSD has 3 partitions. Each partition is an APFS container. Each container contains multiple APFS volumes. Your OS, and everything you care about, is on the second partitio…

By the way, how do you get into OS recovery (not 1TR)? `man bputil` does allude to a distinction between the two, as you mention:

> Boot environment requirements: software-launched macOS Recovery or 1TR.

The only way I know of to get to any recovery mode is by holding down the power button, which the man page says is 1TR (though I know you mention seeing that boot into regular recovery anyway).

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

#89

Post by southerntofu » Thu, Feb 18, 2021, 1:43 PM UTC

lupire wrote: post #87

southerntofu wrote: post #80

Earlier quoted context omitted.

Why, though? Physical access to the hardware should prevent you from accessing existing files (encryption at rest) but should not prevent you from resetting/reusing the device. Does your fridge come with FridgeID? Or a book? Introducing such mechanisms is really hostile to users, especially poorer users of second-hand hardware who have to go through extra (shady) hoops to get a device running just because some rich S…

Who is going to walk a away with my fridge? How about my car? Many users appreciate having anti-theft protections on their easy to physically-access devices, and very few need to wipe of the owner's account. It's great that you have a niche use case, but that doesn't make your case the priority over the main use cases.

> Who is going to walk a away with my fridge?

People would steal your wallet, your jewelry... There's a lot more value to be extracted from a stolen credit card than from a "smart" phone.

> It's great that you have a niche use case, but that doesn't make your case the priority over the main use cases.

You're taking it the other way around. The common use case for first-world software developers is the niche use case for the rest of the world. In the rest of the world (i.e. the vast majority), who can't afford buying new luxury devices, people are more concerned with getting locked out after forgetting their password (or after their kids changed it) or about acquiring a second-hand device, than about "protecting" their device from thieves.

Because this "protection" doesn't protect anything. Once your iPhone is stolen, it's gone. No iCloud lock is going to bring it back, so why prevent other, less-privileged folks from using it when you can't use it? That type of "mine or noone else's" capitalist mentality is actively harming users and destroying the environment

https://www.ifixit.com/News/34072/apples-activation-lock-wil...

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

#90

Post by acomjean » Thu, Feb 18, 2021, 1:45 PM UTC

user-the-name wrote: post #67

superhuzza wrote: post #62

Earlier quoted context omitted.

So that they can use/sell the stolen Macbook, which is much more common than stealing a Macbook to delete the data.

Erasing the drive doesn't let you do this, the Apple ID of the owner is stored elsewhere and you have to log in to restore the machine.

The weird thing is that when my partner turned in an old Mac mini to Apple for recycling they wouldn’t do it because her account was still on there and there was a system password.

But we couldn’t figure out what they were talking about, we had reinstalled the OS. It’s embeded in there somewhere deep.