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

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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.

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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.

I had a check of our internal database, and we do have this recorded there. However, because the current behaviour is by design, rather than by mistake, it’s logged there as a request rather than a bug.

I’ve therefore marked it as tracked, but for the sake of keeping things consistent, I’d like to move this to the Feature Requests section. Would you have any objections @martijntje? I don’t think there are any practical implications (in terms of it being implemented) since the relevant thing is that we have an internal ticket for it.

Is there a difference in prioritization? Because I think this is a (usability) bug, rather than a (missing functionality) feature request, as it makes the device slower and less convenient to use.
E.g. I would prefer the finger print scanner to be fixed before implementing a new feature to do something with the assistent button on 10 III.

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There’s no difference in prioritisation.

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I always felt it was an unnecessary step to first read the fingerprint and then have to lift the finger, wait for the phone to wake up, put back the finger to once again read the fingerprint to unlock. Something that emphasises this impression is that what you are presented with after the first reading not is something useful like the clock or notifications but a lockscreen - which by design signals to the user that “you need to authenticate before you can use me”. User: “@&#?! I just did!”

Well, I do consider this a bug, regardless of whether this is implemented as designed. I’d say the design has a bug then. The fingerprint reader is meant to unlock the phone, not simply to turn on the screen.

Goodmorning from Indonesia, on my Xa2 ultra the fingerprint button on the back has a function of 2 options, to unlock screen after timeout and after reboot with the known arrows instead of pin , so fully functionality here, ps u can reset the fingerprint option in the utilities section.