New Fingerprint Sensor does not work after Screen Replacement

[diebelsalt]

I have replaced the broken screen of my Oneplus 8T (KB2003), where I have used a screen already attached to a new frame including the fingerprint sensor from AliExpress. The delivered screen with frame etc. looked exactly like the original one. This means I actually just had to switch over all parts inside the device. The phone is not rooted (never was) and still uses the stock recovery.

Now, everything works, except the fingerprint sensor. In Android 13 (Oxygen OS 13) the icon of the fingerprint appears on the screen, but the fingerprint is neither recognized nor there is a vibration. I already tried the following things:

• delete all pins and fingerprints and reboot in Android 13
• delete all pins and fingerprints in safe mode and reboot in Android 13
• wipe all data (in the stock recovery)
• factory reset
• downgrade to Android 11 (via local install of the zip), here an error appears if I try to register a new fingerprint: "Error during fingerprint registration, please try again"
• delete all pins and fingerprints and reboot in Android 11
• delete all pins and fingerprints in safe mode and reboot in Android 11

Now the interesting part comes: If I boot the device with the old fingerprint sensor connected (Android 11 or 13), and switch to the new one while the phone is running, everything works. This means I can use the fingerprint of the new screen, register new fingers etc. with the new sensor. Once I reboot the phone, it does not work any longer.

Does anyone have an idea what I could try to be able to use the new fingerprint sensor even after a reboot? Thank you!

 

[Rootk1t]

Does anyone have an idea what I could try to be able to use the new fingerprint sensor even after a reboot? Thank you!

I suppose it's done for safety measures.
It seems there is some fingerprint sensor check validity is happening on boot.
If it's recognized as factory one, it works, if not it doesn't.
In your case you were just hotswapping sensors on running android, so the check doesn't detect it, but on boot, it detects non original one.

 

[diebelsalt]

That would be a pity.

Yesterday I have removed the original fingerprint sensor from the broken display. I did some pictures:

Interestingly, also the small black part located between the actual sensor and the silver part at the cable (first picture) has a small transparent window in the screen.

Now I am considering removing my new screen from the repaired phone and try to exchange the fingerprint sensor. Actually, I wanted to avoid this and bought the display already attached to a (new) frame. At least it would be interesting whether there is an obvious difference between both sensors.

 

[Rootk1t]

Now I am considering removing my new screen from the repaired phone and try to exchange the fingerprint sensor. Actually, I wanted to avoid this and bought the display already attached to a (new) frame. At least it would be interesting whether there is an obvious difference between both sensors.

Thanks for information.
Keep us updated on this case.

 

[JedidroidX]

I would use the msm tool as this would restore to original factory setting and write new partition data according to your hardware. This may register the new fingerprint sensor as authentic and would be calibrated during first boot. It's worth a try, I doubt it would work any other way. You can find msm tools all over xda! Good luck getting it to work!