# mRo-X2.1 Autopilot
PX4 does not manufacture this (or any) autopilot. Contact the [manufacturer](https://store.mrobotics.io/) for hardware support or compliance issues.
This flight controller is manufacturer supported.
- 主片上系统：STM32F427 (opens new window)
- CPU: STM32F427VIT6 ARM® microcontroller - Revision 3
- IO: STM32F100C8T6 ARM® microcontroller
- Invensense® MPU9250 9DOF
- Invensense ICM-20602 6DOF
- MEAS MS5611 气压计
- Size: 36mm x 50mm (Can be ordered with vertical, horizontal or no headers installed)
- 安装点：30.5mm x 30.5mm 直径 3.2mm
- 重量: 10.9g
The diagram below provides a side-by-side comparison with a Pixhawk 1. The mRo features almost identical hardware and connectivity but has a much smaller footprint. Major differences are updated sensors and Rev 3 FMU.
- 2.54 毫米头：
- GPS (UART4) with I2C
- CAN Bus
- PPM 输入
- Spektrum 输入
- RSSI 输入
- sBus 输入
- sBus 输出
- LED 输出
- Offboard microUSB connector
- Kill Pin output (Currently not supported by firmware)
- AirSpeed Sensor
- USART2 (Telem 1)
- USART3 (Telem 2)
- UART7 (Console)
- UART8 (OSD)
# PX4 BootLoader Issue
By default a mRo X2.1 might come preconfigured for ArduPilot® rather than PX4. This can be seen during firmware update when the board is recognized as FMUv2 instead of X2.1.
In this case you must update the BootLoader using BL_Update_X21.zip (opens new window). If this correction is not carried out your compass direction will be wrong and the secondary IMU will not be detected.
The update steps are:
- Download and extract BL_Update_X21.zip (opens new window).
- Find the folder BL_Update_X21. This contains a bin file and a subfolder named /etc containing an rc.txt file
- Copy these files to your micro SD card's root directory and insert it into the mRO x2.1
- Power on the mRO x2.1 Wait for it to boot and then reboot 1 time.
This product can be ordered at the mRobotics® Store (opens new window).
Most users will not need to build this firmware! It is pre-built and automatically installed by QGroundControl when appropriate hardware is connected.
To build PX4 for this target:
The board is documented on the mRo hardware repo: x21_V2_schematic.pdf (opens new window).
# Serial Port Mapping