Fingerprint reader does not unlock when display is off

REPRODUCIBILITY (% or how often): 100%
BUILD ID = OS VERSION (Settings > About product): Any version with fingerprint support
HARDWARE (XA2, X10, X10 II, …): XA2, 10
UI LANGUAGE: Irrelevant
REGRESSION: (compared to previous public release: Yes, No, ?): I think this bug exists since the start of fingerprint support.


Unlocking the phone with the fingerprint reader when the screen is off does not unlock the device. It merely switches on the screen. A second scan is required to actually unlock the device or, alternatively, one has to wake up the screen first by pressing the power button before using the fingerprint scanner.


A device with a stored fingerprint and screen that is turned off.


  1. Add a fingerprint to unlock the device
  2. Switch off the screen
  3. Try to unlock it by pressing the finger against the sensor


The screen lights up and the phone is unlocked


The screen lights up, but the phone is not unlocked.


(Please ALWAYS attach relevant data such as logs, screenshots, etc…)


Is that not a feature? :wink:
At least this is since years like this:
display off - fpd wakes and unlocks device
display off and device locked - first fpd wakes display and second unlocks

1 Like

It’s indeed been like this for quite a while. I wouldn’t call it a feature, though.

If I want to wake the display I press the power button. If I want to unlock the device I use the fingerprint reader.


But only one single control for two functions!
It’s not a bug.
It’s a feature!
bzz, bzz and there you are!

Apparently waking up is so different from unlocking that it cannot be done in one action. (I think there was something about this on TJC)
So neither a feature, or (technically) bug, but a slightly annoying limitation.

On both the X and 10 II they are the same thing - so not really an option for many people.

At least on 10 II there is another option: magnetic case. Open case → wake display, fingerprint → unlock :slight_smile: The only downside is the (un)availability of magnetic cases. I simply added a magnet to a regular case.

1 Like

Technically, you can just press the power button with another finger.

Bug still present in 4.3

Still broken in 4.4.

That option is also available on XA2.