Enabling USB Device Mode in U-Boot on RDB3 for eMMC Boot

[#1]

Hi,

Recently, several customers have inquired about how to program the eMMC on the RDB3 development board directly via USB in U-Boot. These customers are designing custom boards based on RDB3 without using an SD card or Ethernet, and therefore need a method to flash the eMMC through USB during the setup stage.

By default, USB device mode is not enabled in U-Boot on RDB3. To achieve this functionality, it is necessary to modify the U-Boot and ATF (Arm Trusted Firmware) source code, as well as adjust the USB configuration to enable USB device support in U-Boot. In addition, the document provides guidance on testing the configuration, demonstrating how to use U-Boot commands to verify that the USB storage device is recognized, load the image from the USB into memory, and write it to the eMMC.

In this article, I will share my experience using BSP42 to implement and test this feature. I hope this guide will be helpful to others who are looking to enable USB device in uboot for eMMC programming on RDB3.