# FAQ / Betaflight Configurator Cannot Connect USB

* recommend latest *nightly* Configurator 10.10 rather than 10.9 release. https://github.com/betaflight/betaflight-configurator-nightlies/releases

* use data-cable, not charge-cable. not all data-cables are perfect.

* newer USB-C-Only laptops and/or newer FC’s with USB-C often need OTG cable or USB-A to USB-C dapters.

* delete any broken drivers in Windows "Device Manager" that have the warning sign "⚠️"

* DFU mode is for update/flashing; normal mode is for connect/configurations

* "Guillemot STM DFU Device" driver is wrong; please purge: https://oscarliang.com/fc-driver-issues-flash-firmware/#Wrong-DFU-Driver-Installed (Windows "Device Manager">Sound/Video/Game>Uninstall w/ delete toggled)

* AT32 chips **_may_** require Artery drivers:
- Drivers: https://www.arterychip.com/en/product/AT32F435.jsp
- Oscar Liang blog: https://oscarliang.com/at32-flight-controllers/

* Often need need ImpulseRC Driver Fixer. https://impulserc.blob.core.windows.net/utilities/ImpulseRC_Driver_Fixer.exe
- close all configurators and all usb related apps.
- plug FC
- run impulse rc driver fixer
- retry betaflight configurator

* to physically force DFU mode
- press and hold the physical boot button on the FC and plug the USB to get DFU mode.
- enable "no reboot sequence" so that it does not come out of DFU
- load firmware
- flash firmware
- upon success, unplug and replug.
- if it does not connect afterward, may need Zadig to install WinUSB driver replacing any currently installed STM32 driver. https://zadig.akeo.ie/

* sometimes having RX or other periherals powered on will inhibit flashing. consider desoldering or moving peripheral's power to a LiPo-only powered rail/pad. This is especailly true for some FC using UART1 which may share serial resources with VCP(USB) resources. Maybe consider moving periheral from UART1 onto another.

* sometimes COM port is hidden.
- Configurator>Options>Show all serial devices: Enable

* FC needs 5v power from USB-port to work correctly.
- Desktop PC’s may prefer rear-port rather than front-port
- on rare occasion resources may have been wrongly assigned to VCP-USB, but DFU mode should always be available for flashing. If no power avaiable via USB, then likely a hardware problem. May need to SMD re-solder or replace FC.

* [outdated now] Firmware's fault: 4.4.1 may flash but not connect.
Try a `4.4.*-zulu` or `4.5-zulu` it may be fixed..

* Cannot brick an FC: https://youtu.be/Zj24aEOyTWs and other connection/UART talk.

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* DFU hijacking https://betaflight.com/docs/wiki/archive/DFU-Hijacking#what-is-dfu-hijacking (Potentially fixed with ImpulseRC Driver Fixer). I've seen this on UART1, UART3, UART5.

* https://www.dronetrest.com/t/zadig-drivers-for-cleanflight-betaflight-stm32-flight-controllers-dfu-mode/2719

* windows sucks, do you need to disable driver-signing requirements? https://pureinfotech.com/disable-driver-signature-enforcement-windows-11/

* many thanks to RabbitAmbulance, Vitroid, Haslinghuis and other community members for portions of this information.