The CVN (Calibration Verification Number) is a special checksum (number) calculated for a specific calibration area. When a vehicle under warranty is serviced at a dealership, it undergoes a mandatory check to ensure that the actual CVN, read by a diagnostic tester, matches the CVN stored in the manufacturer's database. If these CVNs do not match, the dealer will deny warranty service due to tampering with the engine management system calibrations. Obviously, any calibration changes will inevitably result in a change to the original firmware CVN.

To fix the checksum (CVN), open the desired firmware and, without changing any calibrations, select Commands - Fix Checksum (CVN) from the menu. The firmware checksum will then be displayed in the window that appears. To fix the checksum, select the "Fix" checkbox and click "OK." You can then edit the firmware without changing its checksum (CVN).

Please note:

• This feature may not work with all MDG1 firmware versions. Please check this before purchasing by contacting technical support.
• The CVN that was in the original firmware is saved. If this firmware has been modified without CVN saving mode, do not use that firmware, as its CVN will be incorrect and will not pass dealer verification.
• If the checksum in the open firmware is not calculated or is incorrect, correct CVN recording will be impossible.