Beginner needs help - No Radio was found

[Bionette]

When I turn on the my X9D+ with bootloader mode (2.1.6), I plug the USB cable directly to my MacBook Air. OpenTX 2.1.9 running in my MacBook cannot find the radio. Please help and advise.

[Kilrah]

Use a microSD card reader to put the firmware file on the radio's card in the FIRMWARES directory and update the firmware and bootloader.

[alex998r]

Change USB cable