Remove the back cover and battery to see the sticker. Packaging: Check the original retail box. Secret Codes for Nokia 105 (TA-1203)

Entering incorrect engineering codes can disable the phone's software.

If you are looking for an IMEI change code because your phone isn't catching a signal, try these legal alternatives first:

Ensure your SIM card is active and the device is supported on their bands.

Use the official Nokia Software Recovery Tool if your model supports PC connectivity.

Use an online IMEI checker to see if the device was reported lost.

Requires a specialized "F-Bus" cable or a professional flashing box.