Rita El Khoury / Android Authority
TL;DR Android 16’s upcoming USB Protection feature enhances security by defaulting new USB connections to charging-only when the device is locked.
This security measure may interfere with fast charging, as many protocols require data negotiation between the phone and the charger to work.
If your phone isn’t fast charging, a simple workaround is to unlock the device and then reconnect the USB cable.
Of all the new features in Android 16, Advanced Protection is one of the most important. It’s a powerful toggle that activates numerous security features across the operating system and in compatible apps, shielding high-risk users from intrusions and sensitive data leaks. With a single tap, it enables over a dozen features, with more planned for future updates.
Later this year, Advanced Protection will add a feature called USB Protection, designed to guard against malicious USB devices. There’s one caveat, though: It may not work correctly with your phone’s fast charging capabilities. Fortunately, there’s a simple workaround.
According to Google, the USB Protection feature “prevent[s] physical attacks attempting to exploit the USB port by defaulting to charging only for any new USB connection while the device is locked.” By disabling data access at a hardware level, this feature stops USB-based attacks that exploit vulnerabilities in the device’s USB stack or attempt to brute-force the lock screen. Once the user unlocks their device, USB data access is restored, allowing them to use any peripheral.
If you plug in a USB device while your phone is locked, however, you’ll have to unlock it and then reconnect the peripheral to get it working. We already knew this would be the case when we reported on the feature earlier this year. What we didn’t know at the time, though, was that this behavior would also affect fast charging, at least in some cases.
In the latest Android Canary release, we noticed that Google has enabled the USB Protection feature and also tweaked its implementation. For instance, the notification that appears when you plug in a USB device while your phone is locked has been reworded and now includes a “silence” button to snooze it until you restart.
Mishaal Rahman / Android Authority
While digging through the build for other changes, we spotted new text strings that explicitly state you may need to unlock and reconnect your device for fast charging:
Code Copy Text Unlock device for fast charging and data transferring You may need to unlock and reconnect your device for fast charging and data transferring Unlock device for fast charging You may need to unlock and reconnect your device for fast charging
While it’s not entirely clear why this happens, it could be a consequence of how fast charging protocols like USB Power Delivery work. To prevent damage, these protocols require a data-based negotiation between the charger and your phone to determine the correct voltage to use. USB-PD uses two dedicated lines called configuration channels for this process. Although these lines aren’t used for general data signaling, Advanced Protection might still disable them out of an abundance of caution.
When I tested this on my Pixel 8 Pro, however, I didn’t notice any difference in charging speed when I plugged it in while locked versus unlocked. I got the same speeds from several USB-PD chargers in both scenarios, and I never saw a warning about needing to replug my device. This could be because USB-PD isn’t affected or because the fast charging warning simply isn’t implemented yet. It’s possible this issue only affects proprietary fast charging protocols that use traditional USB data lines, but it’s too early to say for sure.
In any case, it’s clear that Advanced Protection’s new USB Protection feature will affect fast charging in some situations. The good news is that the workaround is simple: If you see the warning, just unlock your device and reconnect the charger.
Since this feature is live in the latest Canary release, it will likely debut in Android 16’s second quarterly platform release (QPR2). That release is scheduled for December, which lines up with Google’s promise to add USB Protection to the Advanced Protection suite later this year.
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