The Sony XZ3 is a high-end smartphone that comes with advanced features and a sleek design. However, like any other device, it's not immune to issues. One common problem that users may encounter is an invalid or lost IMEI (International Mobile Equipment Identity) number. This can occur due to various reasons such as software issues, hardware damage, or improper flashing of firmware. In this guide, we'll walk you through the process of repairing the IMEI of a Sony XZ3.