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When I plug my iPhone or iPad into my laptop with the USB cable, it doesn't start charging until I unlock the device with touch ID or code. Is there a way I can change this behavior? I don't think it used to work that way (years ago), and now I often forget to unlock it, so I think a device is charging and then hours later realize it's not.

To clarify, I don't have to leave it unlocked. I unlock it, then the battery icon changes to indicate it's charging, then I can lock/sleep it again.

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What you are observing is due to a security related change made in iOS 11.4.1.

Starting with iOS 11.4.1, if you use USB accessories with your iPhone, iPad, or iPod touch, or if you connect your device to a Mac or PC, you might need to unlock your device for it to recognize and use the accessory. Your accessory then remains connected, even if your device is subsequently locked.

This setting can be accessed on your iPhone/iPad by going to Settings app → Face ID & Passcode → USB Accessories.

When the USB Accessories setting is off, as in the image above, you might need to unlock your iOS device to connect USB accessories.

This is turned off by default for security reasons. If you turn it on, your iPhone/iPad will start charging instantly, without unlocking it's connected to your laptop.

  • Thanks. Mmm... I wonder what the security issue is. It would be nice to only enable it only for my laptop, not any computer. Since I don't understand it the security issue, I may just leave it off. – Rob N Aug 18 at 17:27
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    @RobN when you plug your iphone into the computer, you allow that computer to see your camera roll. if you turn this off, then anytime you plug in your iphone the computer will immediately be able to see your pics, without any prompt on the iphone. now imagine if one of those public USB hubs at an airport was in fact a computer that tried to scrape images off peoples phones. your images would be scraped without you knowing. That is why the prompt is important. – basher Aug 19 at 3:32
  • @basher: That's not the case. Photos are not exposed to the computer connected unless you grant permission by unlocking. The update in question increased security further to not even interface with connected USB devices at all, to close off the attack surface that was being used by blackhat devices being sold to law enforcement and rogue nation state actors to access the contents of seized devices. – R.. Aug 19 at 4:14
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    Okay, but nobody is asking to "recognize and use the accessory" (which it isn't, anyway), just to draw power, which doesn't require exposing any USB endpoints at all (yes, you need to connect to do power negotiation, but you don't need to offer up any useful interfaces in your descriptor or respond meaningfully to anything the host sends). This seems like a decision that decreases security by inconveniencing users until they turn security options off. – hobbs Aug 19 at 4:38
  • @hobbs Seems correct. If you imagine that the public USB charging station is an evil computer, you can't use it. – Barmar Aug 19 at 5:59

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