The default code is 12345 . If you'd like, I can:
Flashing or rewriting the NVRAM data on a Nokia 105 without expert knowledge frequently corrupts the device’s firmware. This results in a "hard brick," rendering the phone completely dead and unable to power on. nokia 105 ta 1203 imei change code
Dial *#0000# to view the software version and model details. The default code is 12345
If you bought a used phone, you can verify that its IMEI is not blacklisted (i.e., reported stolen or lost). Use official resources: Dial *#0000# to view the software version and model details
To summarize: That is a myth perpetuated by old Nokia feature phone hoaxes from the early 2000s (e.g., the fake "IMEI changer" codes for Nokia 3310).
The Nokia 105 TA‑1203 is a single‑SIM device, so only one IMEI will be displayed. Newer dual‑SIM models show two IMEIs.
Remove the back cover and pull out the battery. You will find the legal IMEI printed on a white sticker inside the battery compartment. The Myth vs. Reality of Secret "IMEI Change Codes"