This section describes what to do when an Android phone with an in-screen fingerprint sensor started to fails to register a fingerprint.
May be solved by recalibration
Android smartphones with in-screen fingerprint sensors may become inoperable or fail to register fingers, especially during bootloader unlocking.
This may be caused by the loss of calibration data stored in the persist partition.
In such cases, the dedicated tool Relife RL-071B can be used to repair the problem.
(Of course, this is not possible if the sensor is physically broken…)
Relife RL-071B comes with yellow, blue, pale orange, and black rubber.
The rubber can be inserted into the hole in the main unit.
The color of the rubber required depends on the smartphone, but this single unit can be used with calibration tools from various manufacturers.
Calibration can be performed by pressing the rubber against the in-screen fingerprint sensor as instructed.
Instructions are included, and some manufacturers have written instructions.
When calibrating, it is better to calibrate in a room that is as dark as possible to increase the success rate.
How to calibrate OPPO/OnePlus/realme phones
First dial *#899* in the phone app.
Select “AfterSale Devices Calibration” and type 6776 to proceed and press back button and “Pass” until “Finger print Optical Calibration” opens.
Follow the on-screen instructions to place the rubber on the sensor.
How to calibrate Xiaomi phones
First, dial *#*#6484#*#** in the phone app.
CIT will open, then select “Additional tools” from the menu button in the upper right corner and press “Fod fingerprint calibration”.
Follow the on-screen instructions.
How to calibrate REDMAGIC phones
First, dial *#9959* in the phone app.
Follow the on-screen instructions to apply pale orange, then black, then pale orange to the sensor, and if you see any errors, you are done.
How to calibrate vivo phones
Download the VIVO校准电脑软件 from the site below. (It is also mirrored here. Password: vivo)
If you dial *#588# in the phone app and activate the Debug port and run the AT command tool, you should be able to go to the calibration menu.
If you have one Relife RL-071B, you can immediately repair the in-screen fingerprint sensor when it becomes unusable, so try it if you have ever had trouble with the in-screen fingerprint sensor during bootloader unlocking.