Firmware Zte Blade V40 Smart - If IMEI is lost, restore using Maui META tool (Windows only) or engineer mode -> connectivity -> CDS information . Ensure your phone is charged to at least 50% before starting any update to prevent a shutdown during the process. Firmware ZTE Blade V40 Smart Power off the phone. Hold the Volume Down button and connect it to the PC via USB. If IMEI is lost, restore using Maui META