The IMEI is a unique 15-digit number used to identify a device on a mobile network. If a phone displays "Invalid SIM," "Emergency Calls Only," or shows a generic IMEI such as 135790246811222 , the device cannot connect to a cellular network.

One day, a customer named Wang came to Jing's shop with a broken Nokia 3310. The phone had been dropped in water and had stopped working. Jing fixed the phone's water damage, but when he tried to activate it on Wang's network, the phone wouldn't register. The IMEI was corrupted.

: You should only use these tools to restore the original IMEI found on the device's sticker or box if the software has become corrupted. Popular IMEI Repair Tools for Keypad Phones

If you are a technician working on legitimate repairs for feature phones (China keypad mobiles), here is a technical overview of the tools and methods commonly used in the industry. 🛠️ Common Software Tools Most Chinese keypad phones use MediaTek (MTK) Spreadtrum (SPD)