If you write the IMEI and it still shows "Invalid," your NVRAM chip might be physically damaged or "Read-Only." Important Legal Notice
For many RDA-based feature phones, you can access the engineering or IMEI write menu directly from the keypad.
Enter the 15-digit code found under your phone’s battery and hit . Restart the device immediately. Best Software Tools for Coolsand RDA Repair
This is the official utility for RDA chips. It allows you to read and write NV data. Deep partition repair.
If the keypad codes do not work (which happens if the manufacturer has disabled the Engineer Mode), you will need to use a PC-based tool via a USB data cable. 1. RDA Service Tool (Free)
IMEI repair is intended for restoring a device to its original factory state using the number printed on the device’s sticker. Changing an IMEI to a different number is illegal in many jurisdictions. Always use the original IMEI associated with the hardware.
The is a widely used chipset in budget-friendly feature phones and some older smartphone models. If you find your device displaying an "Invalid IMEI" error after a firmware flash or a factory reset, you likely need the specific service codes to restore its identity.
– While this usually just shows the IMEI, on some RDA firmware, pressing "Options" or "Edit" here allows for direct input. *#9646633# – Common for generic Chinese chipsets. *#8232# – Specific to certain RDA8851 models. *#3646633# – Standard MTK/RDA hybrid code. How to use the code: Open the Dialer/Keypad. Type the code carefully. Navigate to Para Set or Connectivity . Select IMEI or Write IMEI .
Miracle Box is arguably the best paid tool for Coolsand RDA IMEI repair. It has a dedicated "RDA" tab.
If the phone just starts charging when plugged in, you haven't hit the boot key. Common RDA boot keys are the 'Center/OK' button, 'Dial' button, or '*' and '#' together.
