Here comes the working solution to MPM ECU Tuning Tool can read ECU/TCU but can’t write it and asks for credits.
Users cannot save the file after making modifications directly. Only save after reading PCM/ECU/TCU. It avoids credits in this way.
Read data, after the modifications, write the data back, after that, read it again, finally save the data.
Check: MPM Tool How to Write & Save ECU/TCU data without Credits?
Step 1: Read ECU/TCU data and save
Step 2: Make modification
Step 3: Write the data back after making modification
Step 4: Exit VCM Editor
Step 5: Read again and save data.