Bms 5s DFU mode unable to enable on power up

Good day and hope that you are all well.
Im getting more into the system functionality and and also how the code works and making changes and uploading via the Stlink port .
However on the 5s board i am wanting to use the usb port using DFU option . I have tried to power on the unit and holding the button s2 for dfu mode for 3 seconds does not enable the usb .
I dont have any detection under device manager which leads me to believe that dfu mode is not set .
If i look at the bms it has booted and this means that Boot 0 might not be activated , i have checked the circuit and all seems correct . Im not sure what is the procedure to enable DFU mode on the 5s bms ? Should it be powered by the batteries or purely usb connectivity ? And at what stage does one plug in the usb cable and press the s2 button ? or the s1 button if the batteries are connected ? I thank you in advance .

The SW2 button enables the DFU mode. This should work even without a battery connected (board powered via USB). When the DFU mode is active, the device should not start up normally, i.e. no LEDs should be on.

SW1 activates the board via the BQ76920 LDO. It is used after successful flashing of the firmware to switch on and off the battery.

So I agree that your device doesn’t seem to be in DFU mode. Maybe something is soldered wrong? The process seems to be OK. And DFU mode works fine with my BMS.

thank you . i did manage to get it working, but after a few attempts seems the Stm32 is now corrupt . The Dfu uploader does upload the dfu file correctly after it has been converted but board never posted …