You could totally laser cut a hole in the back of an iphone to replace the battery. You might need to remake a few ribbon cables, but then you'd have yourself a removable battery.
You could start a business that can cut the required hole, and then sell batteries that fit the hole with the case pre-glued on. (you'd replace a square of the back of the iPhone whenever you replaced the battery)
It isn’t drm, a warning shows up on boot if the battery replacement was done unofficially. It has no functional impact on the device.
The reasons behind it are pretty strong. A lot of repair stores use second hand, or fraudulent parts which damage the user experience. So for an owner getting a repair, if they don’t see warnings, they know the repair was done right. And as a buyer, you can tell the phone is using all official parts.
It’s also likely used to ruin the resale value of stolen parts from the factories.
You could surely still have this for non-genuine / used batteries, but here we have a genuine battery coming straight from Apple throwing that warning. Just let 3rd party repair shops buy them at a reasonable price and don't throw the warning if it's unused.
Edit: and preferably let them buy the batteries in bulk, without having to have the phone on hand which just causes unnecessary delays.
It’s because a lot of them are genuine batteries which have either been stolen from factories, second hand from other phones, or have had the id ripped from a genuine battery.
The thing is there is very little drm here. There is no complex crypto chip on the battery. The battery just says “my id is 36382” and the phone goes “that’s not the id I expect”. Which makes it impossible for fraudulent parts to replicate since even making the chips respond identically won’t work.
Yes it has some downsides. But I think the trade off is reasonable. If you want to do an unofficial replacement, you still can. Just ignore the notification that shows on boot.
Surely this is easy for an unofficial battery to replicate... You just have a step during installation where you put the new and old batteries face to face briefly so the data lines touch, and the new battery can read the old batteries ID and memorize it?
There were some devices that would let you copy the ID over but they fell out of popularity / couldn't keep up. Just not worth it for a low margin item I guess.
You could start a business that can cut the required hole, and then sell batteries that fit the hole with the case pre-glued on. (you'd replace a square of the back of the iPhone whenever you replaced the battery)