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Comment by xondono | Hacker News Reader

A lot of people are claiming this is about screwing with third party, but there’s a lot of good technical reasons to do things like that.

For instance, the serialization of batteries (they’re not only serialized, they have a symmetric key pair) is a key safety feature.

I’ve designed devices with the same ICs and screwing up the configuration (or copy pasting the config and install cells with different chemistry) can set them on fire.

In the case of the screen, I think it’s much of a security issue.

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> In the case of the screen, I think it’s much of a security issue.

I default to skepticism on this sort of explanation, especially when it involves Apple and third-party repair.

Of course, it might be possible to devise a very sophisticated attack using the screen's hardware interface and Face ID as a vector. If the iPhone was a security-hardened specialty device, I might find that to be a valid reason. It isn't; it's a consumer device, and one that's not terribly hard for sophisticated attackers to compromise, e.g. https://www.wired.com/story/apple-imessage-zero-click-hacks/

The iPhone is one of the most desirable attack target in the world. An attack that can access locked phones is extremely valuable. From the police to spy agencies to totalitarian regimes, everyone would buy your stuff. See NSO.

if you absolutely don't want your iPhone broken into, don't use FaceID at all; this case of "disables FaceID" in that case would be your best friend.

Under what circumstances exactly would it be a safety or security issue to replace one genuine OEM part with another genuine OEM part, identical in all ways except for the serial number?

Perhaps to prevent (or at least make it harder for) someone shorting around the security it is supposed to provide, i.e. by emulating or modifying the replacement part - not that that'd really stop the determined ones

It's a safety issue to replace some, but not all of the cells in a Li-ion battery with cells that are not the same age and condition. Since smartphone batteries are almost always a single cell, it's a non-issue.

Another scenario I can imagine is a charge controller reducing the maximum charging current as the battery ages based on information stored in the controller's memory, which would be incorrect if the cell is replaced. Of course, it would be unusual to replace a cell with one in worse condition, so it would also be surprising for that to be a safety concern.

Keep in mind that the check done inside an iPhone doesn't prevent the failure mode you describe. After all the phone only checks the microcontroller attached to the battery, not the actual cells(if that's even possible in any way).

> not the actual cells(if that's even possible in any way).

It isn't, but there are some controller circuits that switch off permanently if the voltage falls out of range, making changing cells more difficult.

It wouldn’t, OEM batteries can be swapped with no issues, it’s non-genuine parts what causes issues.

On iPhone 12 and moreso on 13, many genuine OEM parts cannot be swapped by anyone other than those authorized by Apple.

AFAIK, that’s only the case for the screen, and there’s a warning when swapping the rear camera.

(Some) Functionality is also lost on the front camera, faceid sensor and battery.

https://youtu.be/8s7NmMl_-yg

It’s not just a warning. Functionality is flat out disabled. Swapping parts between 2 iPhone 13s boinks them.

It would not be a safety issue indeed only until the replacement part includes some mitm hardware that tampers the face id authentication flow. And this can be planted into the genuine looking replacement part as well.

I expect that at least one of these things would have to be true:

1. The MITM hardware could be installed into the screen that's already paired with the iPhone, so the serial check wouldn't help

2. The MITM hardware would make the screen look non-genuine regardless of serial, so the serial check wouldn't be needed

Oh I absolutely think the primary reason for this is an amoral technical reason (please note I said amoral not immoral). But I also think given Apple's aggressive history of trying to fuck with 3rd parties. It would be naive to think that wasn't an important factor in this design decision. Even with the most charitable interpretation, someone knew that this would fuck with third parties, and instead of trying to avoid it. They're going with the solution, again with the most charitable interpretation, appears to look like they're obstructing 3rd party repair.

I pretend to be a security expert on TV; and I fully support the decision to disable face id when there might be a hardware mitm attack. But there's options available to Apple that allow you to have security and 3rd party support.

But they're clearly still making decisions that obviously obstruct user choice. And it's dishonest to pretend otherwise.

ps. I don't think you're being dishonest, you're clearly explaining the rational. My issue generally is the apologists who use these arguments without context, and pretend there's no other options.

> For instance, the serialization of batteries (they’re not only serialized, they have a symmetric key pair) is a key safety feature.

That’s the messaging from the manufacturers which is a big lie IMO. You can validate keys or signatures and give a warning for non-genuine parts. The only reasons to disable features are to prevent competition and, ultimately, to cheat the customer.

It’s not.

Modern batteries integrate the charge controller with the cells, this allows to track the cell life and it allows the management of the chemistry.

Even small changes in chemistry require modifications in the charging algorithm. The only real solution for managing that is bundling the algorithm with the cells.

Setting the wrong configuration can definitely blow the cell up, or cause swelling.

Source: I did blow some cells while designing a battery pack for a portable device

You used to be able to replace batteries in smartphones. Back then none of these things were issues. Its hard to imagine why they would be now.

Sorry, but that is complete corporate-profit-driven-paranoia BS.

Lithium-ion cells are one of the easiest to charge - there's minimum and maximum voltages, and a maximum charge current. Simply limit charge current to the maximum until the cell reaches its maximum voltage, and then wait for the current to drop until it's nearly 0.

Of course, exceeding those limits at the upper end certainly can result in flames, but it's seriously not that hard to charge a cell. But people like to spew plenty of FUD about "complex algorithms" and the like, because the companies who make the ICs stand to profit from that.

Source: I have also worked in electronics on battery-powered devices.

Yes, it’s true that you can implement a pretty simple generic lithium-ion cell charging algorithm that will get the job done for most cells. But that’s not a “modern battery pack”. If you’re trying to eke hundreds or thousands of charge cycles out of cells, implement fast charging, do accurate state of charge estimation under load and in variable thermal conditions —- those things are very difficult to implement generically, and often do have parameters that depend on the specific chemistry being used. Modern devices have to do all of those things.

Yes, TI makes money when people use their battery management ICs with fancy cell monitoring, but I don’t see a lack of price pressure on those ICs. If manufacturers could implement the same features with a less complex, less expensive design, why would all of the modern battery systems, even in competitive sectors like consumer/retail electronics, integrate battery monitoring with the cells?

We're talking about a single cell for a smartphone, not something like an EV battery pack.

Sure, maybe there’s less need for charge balancing in a smartphone battery, but the rest of the constraints still apply - fast charging is hard!

Limiting the current to what the cell manufacturer specifies is not hard.

I don't think fast charging is a good idea anyway because it wears out cells faster, but that's another rant...

It also makes it more difficult for thieves to part out stolen devices to work around activation locks, and so in theory is a theft deterrent.

You know what else would lessen the demand for stolen donor devices? Actually selling the parts.

You can't compete with the price of a stolen part.

Exactly. Serialization, which enables tracking and blocking of parts from stolen devices, works best alongside making OEM parts readily available at-cost to third party repair services.

I can see how this can be a safety issue but IIRC even with genuine apple parts faceID stops working :/

so this only concerns 3rd party repair shops or individuals who dont want to pay apple to replace their screen.

And to add the insult to the injury, the genuine parts are not available, which screws 3rd party repair shops even more.

Surely that’s just a temporary thing as production lines fill their launch orders? I imagine the authorized repairers already have stock coming in Oct./Nov.

The point is that you shouldn't need to be an authorized repairer to purchase a replacement screen from Apple. I don't need to be an official Volvo dealership to purchase any replacement part for my Volvo, as long as I know the part number I can easily buy the OEM part or a replacement and Volvo has no way to stop me.

Surely during the warranty period Volvo mandates that for the warranty to still be valid the part and installation has to go through a chain of custody of some kind? Like the part must be bought from some official vendor of Volvo parts at least?

No? By law both in EU and US if a manufacturer wants to deny warranty cover, they have to prove that whatever you did to the car has caused the issue. So in this case Volvo would need to prove that their own official part broke the car purely because it wasn't bought from them. You are allowed to work on your car yourself and it doesn't affect warranty, a lot of the things that the "right to repair" movement has been fighting for in electronics have been enshrined in law with cars for a very long time.

Another example - Volvo(and pretty much every manufacturer) says in their warranty terms that the warranty is only valid if the car is serviced annually at an authorized Volvo garage. They can say that, but the law in EU clearly states that you can have the annual service done at any vat-registered garage, and as long as "equivalent" parts are used, the manufacturer cannot deny you a warranty claim based on having the service done outside of their own approved dealership. Their own terms and conditions do not and cannot override the law.

How does it work when the customer department at Volvo denies the warranty claim? Do you escalate through small claims court? I’m not familiar with the EU. Does Volvo also have to compensate for time and court fees if so?

No, you just get a solicitor to write a letter based on an opinion from another expert. That is usually enough, companies also don't want to waste time in court.

The same law applies in US, this isn't some EU exclusive thing.

Also, this question applies in general whenever a company doesn't obey the law and your consumer rights - vast majority of the time, they do. But in case they don't you have solicitors, ombudsmen and yes, eventually, courts. It's rare that it gets that stage though.

That still sounds like a lot of work for the potential savings of a few hundred dollars on repairs and parts. It seems that anyone who could afford a new Volvo would be unlikely to take the risk. Insurance companies may after a collision since the repairs could be easily 5 figures but even then it seems dubious they’d replace major components like the engine or steering control with one of dubious origins since they’d open themselves up to liability risk.

I'm not sure what your point is. I'm just explaining that the law explicitly allows you to both

1) have the car serviced outside of the main dealership network and the manufacturer is not allowed to void your warranty due to this.

2) fit aftermarket parts, and the manufacturer is allowed to void your warranty only if they can prove that the part contributed to the fault.

The whole conversation started by me saying that with cars, you can buy original OEM parts without having to obtain the blessing from the manufacturer - with Apple(and other electronics makers) you can't.

>>That still sounds like a lot of work for the potential savings of a few hundred dollars on repairs and parts.

I don't know why you assume this is any work, you just have your car serviced elsewhere, if any warranty work comes up then you just say "I had the car serviced at a VAT-registered garage, as allowed by the statutory consumer rights". Done, works 99/100 times. Do some dealers try to wiggle out of it anyway? Sure. But dealers try to wiggle out of warranty repairs even if you have done everything "by the book" anyway. That's just what they do. In that case you also have to either start involving experts/solicitors/courts to actually make the manufacturer honour their promise to you. Whether it's worth it to you or not, is a different matter entirely.

Ah see this is the critical difference:

‘2) fit aftermarket parts, and the manufacturer is allowed to void your warranty only if they can prove that the part contributed to the fault.’

In the case of electronic products, we don’t assume things that things that look the same, perform the same.

An aftermarket iphone screen for example could even be from literally the same assembly line but perform so poorly that nobody reasonable could expect Apple to uphold their warranty on a phone with it installed. That’s why QC testing exists.

All other differences can be derived from that basis.

Authorized repairers often don't do repairs on component level, and sometimes ship your device to some place else to have the whole assembly replaced. Which is always much more expensive.

Unless the iPhone 13 is different FaceID does work with genuine Apple parts. My wife and I have cracked lots of them. If Apple doesn’t have them in stock yet because it’s a new phone they will replace the phone. I’ve done it with and without AppleCare.

> In the case of the screen, I think it’s much of a security issue.

logic only a fanboy would dream up. I'm sure the same excuse would be given by fanboys if apple shipped a car and somehow managed to make the windows unreplaceable except by specially signed apple glass.

> For instance, the serialization of batteries (they’re not only serialized, they have a symmetric key pair) is a key safety feature.

Unless Apple itself wasn't opting for crap battery suppliers

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