> And in a fun twist, we’ve confirmed that it’s the exact same cell found in Apple’s MagSafe battery pack. You can swap between them and the phone still boots up just fine.

Are batteries no longer paired with the device? I thought that any battery replacement needs Apple's blessing via their servers, otherwise the phone will claim it's non-genuine.

Starting in iOS 18 this process is self service (although it does require server-blessing and has to be done online) - there’s a built in Repair Assistant app that will guide you through the process.

Also, the phone has always functioned with an aftermarket battery, just with a warning, so the iFixit statement could still be true in that situation too.

My immediate thought was that the battery packs would be a convenient source of replacement batteries for these iPhones, because otherwise genuine Apple parts are notoriously hard to obtain.

I'd bet money that it's just a firmware signature check; and magsafe batteries are signed (since they're genuine).