Bonsoir à tous,
avant de poser notre question sur le forum j'avais contacté DJI, ils viennent de me répondre, je vous copie leur réponse (en anglais) si ça peu servir à quelqu'un:
"We are grateful to assist you with your concern. Sorry that we only provide English service so I try to understand you via Google Translator.
Please confirm that the firmware of the air unit, remote controller, and the Goggles has been updated to the latest version.
Confirm to connect the air unit with the flight controller correctly:
Regarding your issue, please try the steps below:
1. Check the Betaflight Configurator version (check if the beta version is after August 15).
2. Check the Betaflight flight controller firmware version (check if the beta version is after August 15).
3. Check whether the battery voltage information can be shown in the lower right corner of the DJI FPV goggles interface (this step can determine whether the OSD serial port is set correctly).
4 Check whether there is control stick information shown under the receiver interface in Betaflight Configurator (this step is to check whether S-Bus cable and flight controller cable are connected properly and settings are correct).
5. Check whether there is control stick information shown under the remote controller interface in DJI FPV Goggles when pushing the control stick (this step is to check whether S-Bus cable and OSD serial cable are set properly).
Common issues and solutions:
1. The issue does not occur when the protocol between the air unit and flight controller is switched from HDL to S.Bus, while the issue occurs when the protocol is set to HDL.
For the version of Betaflight Configurator and flight controller after August 15, DJI_HDL_7ms is removed and changed to sbus_baud_fast to enable the HDL protocol.
To enable the HDL protocol, enter the CLI command mode and input “set sbus_baud_fast = 1”.
Due to modifications of Betaflight, the DJI HDL protocol is deleted and Sbus_baud_fast is added.
2. The issue occurs whenever the protocol is set to S.Bus or Sbus_baud_fast (HDL).
Please check the soldering cables and check if the port is soldered properly and if the port is open. If the issue persists, there is an error with the third-party flight controller welding settings.
It is recommended to contact a third-party flight controller manufacturer to confirm which serial port of the ground station corresponds to the Sbus interface marked in the flight controller.
3. There is no control stick operation display FPV googles remote controller interface (the drone's voltage is not displayed), but it can be seen on the Betaflight Configurator.
The OSD information is not transmitted to the flight controller, which means that there is an error with the cable on the OSD serial port or the port on the Betaflight is not open.
There is also a case where the welded serial port and the remote controller receiver port is the same, which causes mutual signal interference. It is recommended to contact a third-party flight controller manufacturer to confirm which serial port of the ground station corresponds to the Sbus interface marked in the flight controller.
Please have a try. Thanks."
merci encore à We Are FPV pour votre aide qui avait été précieuse