The SN on the mobile phone's outer packaging box does not match the serial number in the phone settings, leading to the belief that the device is a refurbished unit.
SN stands for Serial Number, which is the product's serial number and serves as its identity card, also known as the machine code, authentication code, registration application code, etc. It is introduced to verify the "legal identity of the product."
The serial number in the realme phone settings under "About device" and "Status information" is the chip ID of the phone, not the SN on the outer packaging box. It is a recognition identifier for the phone's chip.