To solve the issue, you can try the process below:

Formatting the calculator:

Step 1: Press and hold the <2nd> key.

Step 2: While holding <2nd> key pressed, remove a battery, and put it back; you will get a screen with the message "Waiting .... Install operating system now ''.

After these steps, you will need to update the Operating System (OS).

Please follow this link for Updating OS Process by clicking here. (English).

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