Are you trying to fix a message, or are you just looking to update your SDS dongle for the new year?
Ensure you are using the file for the PLUS model and not the older "New" or "Old" versions of the 2500 HD. Download Geant 2500 PLUS RETOUR OFFICIEL FBENSAT bin
Do not turn off the power while the progress bar is moving. Are you trying to fix a message, or
This means your current software is too new to be rolled back via USB. You may need to use a RS232 Loader tool and a PC to force the flash. Download Geant 2500 PLUS RETOUR OFFICIEL FBENSAT bin