"Failed to open USB device!" when updating the Firmware of my FC through Betaflight

[alex22566]

I am trying to update the Firmware of my FC and it all works fine until i try to actually flash anything.
The FC gets auto-dedected and firmware download also works, even when i try to install the firmware the Bootloader PORT shows up but then i get a error message saying: Failed to open USB device!

I don`t know whats the problem
Tried different cables, fixing the drivers and even another computer.

I use a T-Motor F7 flight controller

Hope someone can help me.

[haslinghuis]

Try force DFU from setup tab or cli bl command or power on with boot button pressed.