Sharp PN-L803C Service Manual page 141

<Caution>
- When x mark is attached to the icon of "Reception", the touch pen is in the sleep state and [Advanced] button cannot be clicked (the
character is grayed out).
In this case, have the touch pen in a hand and shake lightly, and click after waiting several seconds until a character becomes black.
- When the above errors come out after clicking [Advanced], click [OK] and return to the window of "Touch pen settings", then have the
touch pen in a hand and shake lightly, and click [Advanced] again after waiting several seconds.
4) Click [Test Information] in Advanced window.
5) Click [Firmware update] in Test information window.
Current firmware version of pen adapter
PN-L803C_80TC3 FIRMWARE UPDATE PROCEDURES 5 - 18