The ConnectCore 6UL platform uses U-Boot (Universal Bootloader) as primary bootloader. U-Boot is an open-source project. You can find standard documentation about commands, environment variables, Flattened Device Tree support, and more at www.denx.de/wiki/U-Boot/Documentation.
About this guide
This guide only describes specific changes made to the standard U-Boot by Digi International.
U-Boot for ConnectCore 6UL is based on standard U-Boot v2020.04 plus NXP patches at https://source.codeaurora.org/external/imx/uboot-imx.
The U-Boot for ConnectCore 6UL supports the following interfaces:
UART5 for console (115200/8/N/1)
10/100Mbps Ethernet on SMSC LAN8720 PHY (RMII)
One-Time-Programmable (OTP) bits
USB device for Fastboot communication
Fastboot protocol is a mechanism for communicating with bootloaders over USB. It is designed to be used across a wide range of devices and from hosts running different operating systems.
Fastboot enables you to boot and control your device, including:
Running any U-Boot command on the target from your host machine
Downloading images and files directly into RAM
Programming and erasing entire partitions from NAND
To start Fastboot on your device, run the
=> fastboot 0
This leaves the device awaiting communication from the host through the selected USB interface. You can use NXP Universal Update Utility (uuu) in your host machine to communicate with the device.
See the uuu repository for additional information.
Carrier board version and ID
Digi uses non-volatile media to store the carrier board version and ID. See Carrier board version and ID.