If the device is "bricked" or has lost its partitions, technicians use

After NVRAM restoration, the IMEI may still be generic. Use Method 1 or 2 again to write your specific IMEI.

The user configures the tool with the firmware's database files and enters the original IMEI.

If you need the exact or Maui META database for TB-8504X , let me know – I can guide you to legitimate sources (no piracy).