Disconnect the pad from the power supply. Touch the upper left corner of the display with the pen. While holding the pen, reconnect the pad to the power supply.
As an alternative, you can also recalibrate the device with API methods or the signoSign/2 application software.
After rebooting, the LED lights up orange. Two intersecting lines (like a plus sign) will appear on a white background in the upper left corner of the display.
Use the pen to tap the midpoint of the two intersecting lines.
Afterward, the same symbol appears in the lower right corner. Tap the two intersecting lines again.
Recalibration is now successfully completed. The pad reboots.
