Perseus lets mask-wearing jailbreakers unlock their iPhone with an Apple Watch

In case you haven’t already heard, Apple recently seeded iOS 14.5 beta to developers with a new feature that permits mask-donning users to more easily unlock their iPhone with Face ID, granted they’re wearing an unlocked Apple Watch. Without this feature, anyone wearing a mask would fail the native Face ID authentication method, compelling users to manually enter their passcode to unlock their device or to approve Apple Pay transactions or App Store purchases.

Given the gravity of just how frustrating it can be to be unable to use Face ID when governments around the world impose mask mandates while in public in an effort to curb the spread of COVID-19, it should come as no surprise that this feature received tons of praise from would-be users. On the other hand, jailbreakers would be stuck with older versions of iOS that don’t natively support the new authentication feature; at least, until now that is…

Perseus is a newly released and free jailbreak tweak by iOS developer udevs that ports functionality similar to what has been introduced in iOS 14.5 beta to jailbroken iPhones that support Face ID authentication.

The way the tweak works is pretty simple: if you’re wearing a passcode-protected Apple Watch, and you’re also wearing a mask, then Perseus will allow your iPhone to unlock when Face ID detects your face with a mask.

One thing worth noting is that while Perseus works similarly to what Apple introduced in iOS 14.5 beta, it’s not exactly the same. The primary difference is that iOS 14.5 beta performs a partial Face ID scan of the visual parts of your face while wearing a mask in addition to performing an Apple Watch connection check. Perseus, on the other hand, will skip Face ID altogether and use your Apple Watch as the authentication key, assuming it’s unlocked, password-protected, and being worn by you in close proximity to your iPhone. That said, one might argue that it’s slightly less secure than Apple’s native implementation on iOS 14.5 beta, but if you’re mindful of your devices, then that shouldn’t be a problem.

Once installed, Perseus adds a dedicated preference pane to the Settings app where users can configure different parameters of the tweak to their liking:

Here, you can:

  • Toggle unlocking with Apple Watch on or off on demand
  • Configure the RSSI threshold (Apple Watch distance required to unlock)
  • Automatically lock iPhone again when the Apple Watch is no longer authenticated
  • Respring your device to save any changes you make

One thing I really like here is that I can adjust the RSSI threshold. RSSI is effectively a measure of signal strength between wireless devices — in this case, Bluetooth. The larger the threshold, the farther away the Apple Watch can be to trigger an automatic unlock. You typically want this value to be smaller, as you want your iPhone to be close to your Apple Watch if and when it gets used to unlock your handset. Too far away, and someone else might be using your iPhone without you knowing.

Given that this is only the first release of Perseus, we’d say it’s an excellent attempt to replicate Apple’s native Apple Watch unlock assist from iOS 14.5 beta. This will give jailbreakers who wear masks an easier way to unlock their devices without having to update to the latest version of iOS and lose their valuable jailbreak.

Those interested in trying Perseus can download the tweak for free from udevs’ repository via their favorite package manager. The tweak supports jailbroken iOS 13 and 14 devices, and if you aren’t already using udevs’ repository, then you can add to your package manager of choice with the following URL:

Will you be taking advantage of Perseus on your pwned iPhone? Let us know why or why not in the comments section below.