Fingerprint sensor suddenly unusable

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Senior Member
Apr 1, 2017
Hi everybody,today I got a very strange problem with my p9 lite (VNS-L31 C432B380). The phone has been rooted ~9 months ago, with SuperSU 2.82 (official) and has twrp recovery.

Today I used my phone as the usual,using fingerprint to unlock it.from 3 PM to 5 PM I didn't use it,it stayed in my pocket (didn't even shutdown it). At 5 PM,i took it,and there , impossible to use the fingerprint,it doesn't recognize any of the 2 fingerprints saved,and doesn't vibrate if I put the wrong finger.
During these 2 hours, nothing happened to the phone,no app updates,no system updates.

What I tried :
-Reboot -> if I'm quick enough and I lock the device right after entering my PIN code,I can use fingerprint to unlock the phone,but 1 time,then it becomes unusable.
-Add a new fingerprint -> as soon as I click on "add new fingerprint",the phone vibrates and shows the image of a fingerprint,like if my finger was on the sensor (but it isn't),and ask me to remove my finger and re-put it,etc....

Like 2 months ago,I noticed that the sensor was a bit damaged,but since the fingerprint sensor was perfectly working,I continued using it :

My idea is that sensor always consider that there's a finger on the sensor,but doesn't do anything about it.

I was wondering if a reset could help (cause I don't what to do :confused: ),can I do it safely from settings,even with root + twrp ?
Thanks in advance,
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