The ConnectCore 6UL platform uses U-Boot (Universal Bootloader) as its 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 v2017.03 plus NXP patches at http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git.
The U-Boot for ConnectCore 6UL supports the following interfaces:
UART5 for console (115200/8/N/1)
uSD card (on USDHC2)
10/100Mbps Ethernet on SMSC LAN8720 PHY (RMII)
One-Time-Programmable (OTP) bits
Carrier board version and ID
Digi uses non-volatile media to store the carrier board version and ID. See Carrier board version and ID.