FP4 fingerprint sensor makes multiple attempts without lifting finger

Hello FP community :slight_smile:
First I’m really happy to be a recent owner of a FP4 and take my part here in the forum :tada:

My question is what the title says. I’ve enabled the option to unlock the phone with the fingerprint scanner without needing to press the button, just by touching it. What I find is when I touch the scanner it rapidly makes several consecutive attempts to read my finger without me lifting the finger between each attempt. This results in a situation where I touch the scanner with the wrong part of my finger, the phone makes 5 consecutive attempts in about 1-2 seconds, which is so quick that I don’t have the chance to realise what happens and then the phone fingerprint scanner gets locked. And I either need to enter my pin or wait for the cooldown period to try with the right finger.

Is there an option to make it so a single touch produces a single fingerprint scanner read? And if that read is “negative” I need to first lift my finger before touching again to make a second read. I think that would be a far better option.

Or could this be an issue with my phone? Are your FP4s behaving the same way?


My FP4 doesn’t behave in the way you describe. Have you already installed the software update that was released yesterday? It is supposed to improve fingerprint sensor performance.

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The update was installed, but I haven’t seen any changes after the update.

It’s not just yours, mine is doing the same thing. The funny thing is it used to work quite well, there were only a few failed attempts to recognize my fingerprint but it’s gotten worse and worse, the new update didn’t make any difference.

I’m contacting support.

Thank you @mosley for confirming. Please post here the progress with support. I’ll try to reach them too and we can compare versions :slight_smile:

Same behavior here, multi attempt and the fingerprint is block for many seconds. That’s why i personnaly used the option to make the fingerprint working on press. But now i’m on Eos and this option is missing. That’s a pity because this behaviour is really annoying !

Same behavior for me, once with FP4OS and now with eOS. It seems the fingerprint sensor works well when pressed instead when “soft touched”.

Did you find the option on Eos to make it available on press ? This option seems to be not included in Eos.

Same problem with my fp4, all updates applied.

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I don’t find this option in eOS but the fingerprints reader works better if pressed.

Hi @mandarin and everyone else having this issue, just an update for you.

Support has responded to my ticket with the following:

1: Check and clean sensor surface

Make sure the sensor is not dirty or scratched: clean the sensor surface with a cotton swab or dry cloth.
Another reason for malfunctioning could be some oily residues on your fingers: please try washing your hands with soap and test it again. If your fingers are a bit wet, it could also affect the functioning of the fingerprint sensor, so make sure to dry them well.

2: Remove and add a new fingerprint

If you already are using the fingerprint sensor and it’s not working well please follow the next steps.

a) Remove the registered fingerprint:

  1. Open your phone’s Settings.
  2. Tap Security.
  3. Tap Fingerprint.
  4. If the device asks you to, enter your screen lock PIN (the code used to unlock the screen).
  5. Tap on the “recycle-bin” icon to delete your fingerprint and confirm to remove it. Your fingerprint should disappear from the list.

b) Reinstall your fingerprint sensor:

  1. After deleting your existing fingerprint, the list will be empty. Tap now on “+ Add fingerprint”.
  2. Follow the on-screen steps. If you don’t have already a screen lock, you’ll be asked to add a backup PIN, pattern, or password.
  3. When you see the message “Touch the sensor” you can start scanning your first fingerprint. Make sure to:
  4. Put your finger on your phone’s sensor.
  5. Press the sensor’s surface with your finger from different angles. In this way, the sensor will be able to also capture partial fingerprints and/or fingerprints when holding the phone in different ways.
  6. You must complete many successful swipes to register the desired fingerprint properly. You will see the progress on the screen.
  7. Once successfully registered, the device will say “Fingerprint added”.
  8. Press “Done” to complete the setup. Remember you can add up to 5 registered fingerprints.

3: Test the sensor in a different environment

The sensor may not work well if the phone is in an extremely hot or cold environment. Please test it again in cooler or warmer conditions once your phone is at average room temperature.

4: Install updates

Make sure to Update your Fairphone to the latest software.

  1. Go to Settings → About your phone → Build number.
  2. Check if your Fairphone has the latest OS: Fairphone OS v.099 (Build number FP4.FP3R.A.099.20220112).

If it’s not running the latest software update, keep reading to know how to update your device:

  1. Connect your Fairphone to a Wi-Fi network.
  2. Go to Settings → System → Advanced → System update → tap on Check for update. Once done, you should either be asked to update or get a message stating “Your system is up-to-date”.

5: Safe mode

To exclude the possibility of a corrupted third-party software, I recommend rebooting your device in Safe mode (support.fairphone.com/hc/en-us/articles/4405445311249). Check if the issue is gone while in Safe Mode. If the issue is still there then, reboot your phone to go out of Safe Mode and proceed with the next step.

6: Factory reset

If you are still experiencing the issue, a factory reset will be necessary:

  1. As this will wipe all your personal data, make sure to, first of all, back up your personal data.
  2. Once the backup is done, perform a Factory Reset. Then, after the reset, do not reinstall any apps nor restore your data, check first if the issue is gone (you can reinstall and restore everything afterwards).

7: More details

If after performing all the previous steps you still need help with the fingerprint sensor, please provide the following information:

  1. screenshot(s) of the error message if you are getting any, or showing the issue.
  2. Picture of the fingerprint sensor.
  3. Did you install any new screen app and/or a different launcher? If so, please uninstall them and try again.
  4. Since when have you been experiencing this issue?

Thank you @mosley for the update. Has any of these steps worked for you?
I’d guess not. It seems like they gave youa very generic answer.
My phone has behaved like this from the first day I bought it and installed all the latest updates. Only the factory reset seems like it could do anything, but given the chances it will actually acomplish anything vs. setting up my whole phone again I don’t want to do it atm.


Unfortunately none of the suggested ideas worked (I haven’t tried resetting the phone as it’s such a hassle). In the follow-up email they suggested that I return my phone to their repair centre in France (I’m in the UK) which normally takes 1-2 weeks excluding the customs procedures. I’d rather keep the phone and reset the fingerprints every 2-3 weeks.

As a side note, I ended up having only two fingerprints set up instead of the original four. Not that it should have anything to do with the issue, but I’m having better results since. One of my fingerprints is recognized more often, the other one is still hit and miss.


Don’t bother with return, it won’t solve anything. Given that many people experience this issue, it is most likely not hardware related. Just keep pushing the support so they actually fix it in the next update. Ideally include a link to this thread.


Me too I think so, also because I don’t have this problem after installed inofficial ROM.


I just filed this regression/bug report (along with the question whether/when FP will implement face unlock for FP4) on support.fairphone.com:

When I put my finger on the power button to scan/unlock the phone, it takes several consecutive (false negative) scans in one term, leading to fingerprint login being (temporarily) disabled. The same thing also happens while registering a finger, and also happens with other fingers, not just thumbs.

For my thumb, the chance to unlock on first scan is 10%(!) success, with multiple unlock attempts (3-4 due to multiple consecutive scans) it’s about 60% with the same thumb registered three times, and about 10% with the thumb registered just once. This only marginally gets better when I increase skin humidity. For me, this is UNUSABLE.

I asked my wife and my son to also register their thumbs and try. It’s better for them, but far away from good: Chance to unlock on first attempt is about 60%, with multiple attempts 80-90%. For them this is UNSATISFACTORY.

To be clear: This is NOT a hardware issue, it’s a new phone, clean sensor, I did all HW checks using the internal app. This is a software bug:

The sensor MUST wait for “sensor released/no finger” (and SHOULD maybe also “wait” 500ms) before even trying to scan a second time. There SHOULD be a UI element asking to release and retry. It MUST NOT scan multiple times consecutively.


The fingerprint sensor works very well on my FP4. It virtually never fails. Actually, I didn’t expect it to work so well.


Face unlock will not be secure and practical without a 3D scanner and IR camera. FP4 doesn’t have those. The only Android phone that had secure and practical face unlock was the Pixel 4. So I don’t think you really want insecure and impractical face unlock :slight_smile:

I don’t have issues with the first fingerprint scanner. Today it said the scanner was dirty. I cleaned my thumb by rubbing it on my clothes and then it worked. I don’t have these multiple attempts in a short time span.

But reading these issues people have, some extra tweaking is indeed needed.


Face unlock may be implemented in more or less secure ways. Using depth is ONE possibility to do so. There’s are studies on that. I’m referring to that published 3 years ago: https://www.consumentenbond.nl/veilig-internetten/gezichtsherkenning-te-hacken. Here’s a english summary on it in case someone doesn’t speak Dutch :wink: See Which Phones Can Be Unlocked by Photos | Tom's Guide – I was quite impressed by my OnePlus 6T that I was never able to deceive. On my OP6T I used a layered approach: Apps with sensitive data wede additionaly secured with either fingerprint (a VERY cool OnePlus enhancement) or password (like for email, using the mechanism the app itself provides). Bottomline for me is that I now know that FP4 does not have face unlock (yet). That is a downer for me since I always used it, very intuitive, very quick.

The other bottomline is that there is a bug with the fingerprint sensor (clearly described above) reproducable with different fingers of different people.

Without an IR camera it’s a pain. In dark environments it won’t work. And without a 3D scanner it’s not secure enough. Since Google will pull the plug out of the Pixel 4, the face unlock software in AOSP will not get that much attention anymore. To do face unlock well, you need quality tested software and hardware. Otherwise it’s a gimmick. I have unlocked phones with my face and I don’t even look like the person. But of course FP can only answer this one. But I don’t expect them to invest in this.