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ELRS-R24-P Specifications:

ESP8285, SX1280/1281
Antenna connector: IPEX MHF 1
5x PWM outputs
RF Frequency: 2.4GHz (2400~2480MHz)
Telemetry power: 12dbm
Receiver protocol: PWM or CRSF
Input voltage: 4~9V DC @ “+” pad
Power dissipation:  45mA(binding), 85mA(wifi mode)
PCB size: 25mm x 13mm
Weight: 2g w/ antenna
Packing: 1x ELRS-R24-P,   1x IPEX MHF1 Antennas

Firmwares:
ExpressLRS MATEK_2400_RX_PWM, or DIY_2400_RX_PWMP,  PWM receiver via 1~5 PWM outputs
ExpressLRS DIY_2400_RX_ESP8285_SX1280,  CRSF Serial receiver via TX and RX
Firmware update via UART or WIFI

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Make sure Receiver and TX module both are running ExpressLRS 2.0

Traditional Binding:
Receivers have ExpressLRS fw V2.0 preloaded without BINDING_PHRASE
Power on and off your receiver three times
Make sure the LED is doing a quick double blink, which indicates the receiver is in bind mode
Use the [BIND] button on the Transmitter Lua script, which sends out a binding pulse
Receiver will switch to slow blink once it has received binding pulse.
Power off and power on receiver again. If the receiver LED switch to solid on from slow blink, it’s bound with your transmitter.

Flashing with ELRS configurator:
MATEK_2400_RX_PWM or DIY_2400_RX_PWMP
If use it as normal Serial receiver, flash it with Target DIY_2400_RX_ESP8285_SX1280

Flashing with ESP_NodeMCU-PyFlasher:
Connect receiver to USB-TTL module(RX-TX, TX-RX, 5V-5V, G-GND)
Connect USB to PC while pressing and holding the boot button in.
open ESP_NodeMCU-PyFlasher
select Serial port of USB-TTL module,  load firmware  ELRS_V2.0.0_NoPhrase_ELRS-R24-P.bin , select “Dual Output(DOUT)”  and “Yes.wipes all data“
click “Flash NodeMCU“
after flashing, Power off and power on your receiver, receiver will enter binding mode(quick double blink).

Troubleshooting:
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.