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Apple Silicon Macs can't boot from external drive if internal drive failed

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141–150 of 422 posts

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#141

General grumpiness about this particular design decision aside, it appears that since the T2 Macs, the main SSD was being used to store core system firmware. On T2 I think it's BridgeOS that sends the EFI image to the Intel side to boot it, and it does the firmware verification and loading. This setup has a benefit; namely, it is now impossible to brick the system with a bad BIOS/EFI flash, and you'll never need to u…

> This setup has a benefit; namely, it is now impossible to brick the system with a bad BIOS/EFI flash, and you'll never need to use a hardware SPI flasher to recover.

Apple-branded SSD module failures are pretty common. Bricked BIOS/EFI images are not.

I've been supporting Mac users for two decades and the only time I've used a hardware SPI flasher was when I needed to pull my firmware image, modify the EFI bootloader to include NVME drivers, and flash it back. It wasn't hard. I attached a clip to the motherboard that connected the chip to a Raspberry Pi.

Seriously, my first mac was an LC. I've never seen a Mac brick itself doing a firmware update.

I had to do that because my Apple SSD died about 5 years into owning the system. That system uses an m2 PCIe port but it's a weird pinout. Apple doesn't sell parts, the local apple authorized shop wanted $250 just for diagnostics, the only thing on ebay were used drives of the same and, and only one company makes an overpriced replacement aftermarket drive for Apple's weird pre-NVME pcie storage connector and they have compatibility issues, underperform compared to much cheaper standard NVME drives, etc.

Thankfully, you can plug in a standard NVME drive via a $10 adapter from ebay.

I was back in business for a fraction of what a used 512GB Apple drive would have cost me, with twice the storage and even more speed over the already fast Apple module. But I had to pull NVME drivers from a later revision of the system and flash them to my ROM.

What pisses me off the most in the whole thing is that Samsung and Apple designed the drive such that when it runs out of write cycles, it completely fails; it doesn't even show up on the PCIe bus.

I'm typing this now on that very system, which is now almost exactly 8 years old. Do you think there will be 8 year old T2 macs? Not if they see daily use.

Repeat after me: user storage for a computer should never be permanently attached.

> This kind of failure (high voltage parts close to low voltage ones, close to liquid damage prone areas, without any underfilling) is documented by Louis Rossmann.

> It is, however, not always feasible or possible to entirely prevent.

It is 100% feasible/possible to entirely prevent.

Don't permanently attach storage on non-mobile devices.

Use conformal coating, something Apple could definitely afford to do with their profit margin on these machines. Even if they just coated the high voltage stuff. In fact, there's no reason T2 mac owners can't buy a can of conformal spray off Digikey or Mouser and do it themselves.

Don't put high voltage components near low voltage ones; especially ones that have user data and are non-replaceable. There's a reason Apple used to have a board for the DC input.

Every T2 mac has a finite lifetime before it becomes completely useless scrap thanks to SSD wear. And it's even worse for the M1 people because reportedly they do a great job of wearing out their SSDs.

This isn't about boot flash reliability or tiny increments in security-for-user-privacy. It's about slowly walling everyone in. Every new update of MacOS, every new hardware update - has put another brick in the wall.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#142

General grumpiness about this particular design decision aside, it appears that since the T2 Macs, the main SSD was being used to store core system firmware. On T2 I think it's BridgeOS that sends the EFI image to the Intel side to boot it, and it does the firmware verification and loading. This setup has a benefit; namely, it is now impossible to brick the system with a bad BIOS/EFI flash, and you'll never need to u…

>whatever failure damaged the SSD is statistically likely to compromise the reliability of the rest of the board Sorry, but how? That's just reads like BS. SSDs have limited lifespans due to the limited write cycles of the NAND chips. So no, what damages NAND does not damage the rest of the board. The more you write and swap to flash, the faster it wears out, taking your Macbook down with it when it dies. Granted, I…

> So no, what damages NAND does not damage the rest of the board. The more you write and swap to flash, the faster it wears out, taking your Macbook down with it when it dies.

Except as explained by the parent, when the SSD dies on an Intel Mac it can be recovered via Internet Recovery via EFI.

Only way to brick that it is to have a bad flash onto the EFI ROM.

On Apple Silicon when the SSD dies, it cannot be recovered as the firmware is also on the SSD and remains bricked which that is that.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#143

Earlier quoted context omitted.

>whatever failure damaged the SSD is statistically likely to compromise the reliability of the rest of the board Sorry, but how? That's just reads like BS. SSDs have limited lifespans due to the limited write cycles of the NAND chips. So no, what damages NAND does not damage the rest of the board. The more you write and swap to flash, the faster it wears out, taking your Macbook down with it when it dies. Granted, I…

How many SSDs have you worn out? I've never managed it.

Apple SSD module failures on portable Macs are quite common. A buddy has a computer repair shop and they do brisk business replacing them. Mine failed about 5 years in.

SSDs are wear items. Especially when they're quite full, it is very easy to blow through spare writes and brick the drive.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#144

Earlier quoted context omitted.

>whatever failure damaged the SSD is statistically likely to compromise the reliability of the rest of the board Sorry, but how? That's just reads like BS. SSDs have limited lifespans due to the limited write cycles of the NAND chips. So no, what damages NAND does not damage the rest of the board. The more you write and swap to flash, the faster it wears out, taking your Macbook down with it when it dies. Granted, I…

I think you are using old information. Any modern SSD should be good for a few hundred to several hundred TB and may reach a PB. It would be very hard to use a personal computer that heavily. Most people would take 20 years or more.

You're forgetting swap. Not to mention professionals in domains like photography, design, video, etc. who might chew through big files frequently.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#145
I've always treated a laptop as essentially disposable - by which I mean that in no way do I rely on it to store my data. It's the device I use to manipulate data. Not only could it break, it could get stolen or damaged at any time.

The bigger issue is that when the drive breaks, they are essentially unrepairable. The only option is getting Apple to swap out the motherboard with another one. On other devices, I'd just swap an M.2 drive. So it's more of a cost issue.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#146

Earlier quoted context omitted.

The other comment points it out correctly, no one wants it price conscious or not. Between the fact that many of them work without issue for years, and the fact that an new equivalent to your 2011 i3 becomes exponentially cheaper over time, repairing it will never be worth it. A Raspberry PI 4 is a functional computer but costs less than just the CPU of that i3 based machine while trouncing it in performance and powe…

At some point, the CPU is almost irrelevant. A huge issue is software locked to a certain motherboard. And the fact that your Raspberry Pi isn’t going to be running x86 software flawlessly and doesn’t come with nearly the same peripherals as a typical laptop (without a lot more cost… but even then, a 1:1 replacement isn’t possible). The assumption that tech gets exponentially cheaper over time, ie Moore’s Law, only a…

Even if it’s not cheaper, the devices aren’t really desirable. Most people don’t want a desktop, they want mobile devices. Lots of people still use old computers and significant upgrades don’t happen in the same generation which is the issue with upgrading Intel CPUs.

x86 isn’t what it was, MS made Windows 11 be able to run android apps, consumers don’t care about x86 software anymore. That’s been true since ChromeOS had been used more often since browsers mattered more than programs that only ran on windows.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#147

Earlier quoted context omitted.

Do you have a threshold for this? I assume that if your laptop wasn't working and all you had to do was take a single screw out then you'd do it, rather than taking it to a repair shop or buy another. Or if the repair cost was extreme, but it was relatively easy to fix it yourself. Your point of view is valid of course. At the same time I believe many people don't have sufficient money to allow them the luxury of nev…

> Do you have a threshold for this? Not OP but I have a really high threshold for this. I don't want to own a house and rent because of this.

Hire from taskrabbit. ;)

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#148

Earlier quoted context omitted.

>whatever failure damaged the SSD is statistically likely to compromise the reliability of the rest of the board Sorry, but how? That's just reads like BS. SSDs have limited lifespans due to the limited write cycles of the NAND chips. So no, what damages NAND does not damage the rest of the board. The more you write and swap to flash, the faster it wears out, taking your Macbook down with it when it dies. Granted, I…

I think you are using old information. Any modern SSD should be good for a few hundred to several hundred TB and may reach a PB. It would be very hard to use a personal computer that heavily. Most people would take 20 years or more.

Video editors have workloads that can write a ton for each project in 4k and 8k resolutions, if its pro res even more. First thing they do is grab the largest fastest storage they can work off externally.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#149

Earlier quoted context omitted.

>> It also wouldn't win you any significant increase unusable lifespan, because when your drive starts retiring large numbers of blocks, all of your blocks are on the verge of failure. That's not true. Blocks degrade when written to. Most files are written once and read many times.

You're forgetting that SSDs use virtual addressing so writes are distributed relatively equally over the whole drive. Even data that is written once and never changed logically will probably move around on the SSD due to garbage collection. The virtualization algorithms are kept relatively secret, but I assume good SSDs will move full unchanged blocks around occasionally to distribute write load more equally on the p…

Yep, wear leveling actually works. On some SSDs, there are SMART indicators to tell you the average, max and min block erase counts, so you can see for yourself that the erase counts are all about the same across the entire drive.

Re: Apple Silicon Macs can't boot from external drive if internal drive failed

#150

Earlier quoted context omitted.

Once again Apple is showing how to do things stupidly. They won't allow you to boot from an external HDD/SSD if the internal one fails. On top of that they make it extremely difficult to replace the internal disk on your own. Carbon Copy Cloner has been my number one program all these years, but I think that Apple is pushing us loyal and technical competent people away. They just want "simple" users.

They want you to take the device to the dealership.

Perhaps, but there’s a security angle to this as well. iBoot is stored on the internal SSD. If you want to bypass the internal SSD entirely for the boot process, you must now trust that any external drives plugged in have non-evil versions of iBoot installed, as the Mac will now have to go to every external device and say “can you tell me how to boot?”. If the internal drive is the only place to get iBoot it makes the security strategy way easier (since the only way to write to it is via DFU connected to Apple Configurator). We know only people with the keys can modify the internal drive, so we don’t have to keep certificates or something else around to verify it is trustworthy. Who knows where the external drive’s copy of iBoot is from.

You could make it so there’s a break glass copy of iBoot on another chip, but then that’s something they can’t update if there’s a bug.

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