after flashing, Power off and power on your receiver, receiver will enter binding mode(quick double blink).
If receiver can’t be flashed via WIFI or BFpassthrough when it come with preloaded firmware. You may recover it by flashing it via UART.
Wire the receiver into the USB-TTL adapter, with TX on receiver connected to the Rx on the USB-TTL, and RX on receiver connected to the Tx of the USB-TTL. Wire 5V and GND of the USB-TTL to 5V and GND of the Receiver. Press the boot button while powering the RX on, and release – the LED should now be solid.
Select the target MATEK_2400_RX PWM or DIY_2400_RX_PWMP, and “UART” for Flashing Method, set your bind phrase and Firmware Options and once done, click on Build and Flash.