Happymodel CrazyF411 ELRS 4 in 1 AIO Flight Controller – 20A 2–4S with Built-in ELRS

Reliable. Integrated. Ready to race.

The Happymodel CrazyF411 ELRS AIO is a versatile all-in-one flight controller designed for 2–4S FPV toothpicks, long-range builds, and freestyle quads. Powered by an STM32F411 MCU with integrated 20A 4-in-1 ESC, built-in ExpressLRS 2.4 GHz receiver, and a robust sensor set, this board packs everything you need into a compact 25.5×25.5 mm mounting pattern.

With Bluejay firmware pre-installed, an upgraded EFM8BB21 ESC MCU, and reliable UART-based ELRS, the CrazyF411 is the ideal choice for performance-focused pilots. Binding and firmware updates are easy through Betaflight pass-through or WiFi — just like the EP1 receiver.

*”ET” and “ER” pads are used for communication with the ESP8285, you can connect the “TX” of FTDI tool to “ET” pad and connect “RX” of the FTDI tool to “ER” pad to upgrade onboard UART ELRS receiver firmware. You need to connect the “+5V” and “E5” pads before that.

Why Pilots Love It

• All-in-one integration — FC, ESC, ELRS RX, OSD, and BEC in one board.
• Powerful performance — 20A continuous / 25A peak ESCs support 2–4S packs.
• ExpressLRS built in — UART-based ELRS receiver with up to 500 Hz packet rate.
• Simple updates — flash via Betaflight passthrough or WiFi, no solder headaches.
• Proven durability — bigger MOSFETs, onboard voltage/current sensors, and barometer.

Quick Specs

Flight Controller:

• MCU: STM32F411CEU6 (100 MHz, 512K Flash)
• Sensor: ICM42688P or BMI270 (SPI)
• Mounting: 25.5×25.5 mm M2
• Size: 32×28×9 mm
• Firmware Target: CRAZYBEEF4DX
• Built-in 5V 1.5A BEC
• Built-in OSD (SPI Control)

ESC (4-in-1):

• Firmware: Bluejay 0.18.1 (DSHOT150/300/600)
• Current: 20A continuous, 25A peak (5s)
• Power: 2–4S LiPo/LiHV (7–17 V)
• MCU: EFM8BB21

ELRS Receiver:

• Protocol: CRSF (UART)
• Packet Rate: 25–500 Hz
• Default Firmware: ExpressLRS v3.0.1
• Firmware Target: Happymodel EP1/2 2400 RX
• Antenna Connector: IPEX

Other Features:

• Built-in voltage/current sensors (scale 110 / 470)
• Bind/update pads (ET/ER/E5) for FTDI tools
• Designed as a drop-in upgrade for Crux35

What’s in the Box

• 1 × Happymodel CrazyF411 ELRS AIO Flight Controller (20A)
• 1 x ELRS T Antenna
• 1 x XT30 Lead
• 4 x Mounting gummies
• 4 x Motor Plugs

In short: The CrazyF411 ELRS AIO is a race-ready flight controller that combines power, simplicity, and ExpressLRS reliability in one lightweight board. Perfect for 2–4S toothpick and freestyle builds, with all the features pilots expect.