Motor choice: Avoid selecting motors with excessively high KV ratings, as motors above 20,000KV are prone to burn.
ESC Firmware
With BB51 ESC solution, F4 2-3S 20A AIO FC V1 is based on BLHeliSuite16714903 with Bluejay ESC firmware, it supports bidirectional D-shot and RPM filtering in Betaflight, offers 24KHz, 48KHz, and 96KHz fixed PWM frequency for options, and custom start-up melodies. F4 2-3S 20A AIO FC V1 default factory setting is 48KHz and it doesn’t recommend upgrading the 96KHz, or it might cause an error in the motor idle setting, not spinning when disarmed.
DO NOT flash the firmware with a shorter interval, otherwise, there will be a certain chance of stalling and burning the flight controller.
Serial ELRS 2.4G RX
Serial ELRS 2.4G RX uses the Crossfire serial protocol (CRSF protocol) to communicate between the receiver and the flight controller board. So the Serial ELRS 2.4G RX is available to support upgrading to ELRS V3 with no need to flash Betaflight flight controller firmware.
Enter binding status by power on/off three times.
Plugin and unplug the flight controller three times;
Make sure the RX LED is doing a quick double blink, which indicates the receiver is in bind mode;
Make sure the RF TX module or radio transmitter enters binding status, which sends out a binding pulse;
If the receiver has a solid light, it's bound.
The Serial ELRS 2.4G RX can be updated via Wi-Fi or Betaflight serial passthrough. Here is the way to update the Serial ELRS 2.4G RX firmware through passthrough.
Plug in your FC to your computer, but do NOT connect to betaflight configurator.
Choose target "BETAFPV 2.4GHz AIO RX".
Flash using the BetaflightPassthrough option in ExpressLRS Configurator.
Connecting External Devices
Please note that the board reserves two serial ports and a standard SBUS port, which is available for the external CRSF protocol receiver or GPS module, and SBUS protocol receiver. You can refer to the below picture.