Build U-Boot#

This module explains how to compile U-Boot.

During Linux development, the U-Boot source code may need to be modified and recompiled. For example, U-Boot must be recompiled if:

  • Enabling features which are disabled in the U-Boot defconfig

  • Disabling features which are enabled in the U-Boot defconfig

  • Modifying U-Boot source code to port U-Boot to a custom board

This section explains how to rebuild the U-Boot source code provided in the Processor SDK Linux package on the Development Host.

There are two methods to build the U-Boot in the Processor SDK:

  • Using the SDK top level Makefile

  • Using the U-Boot top level Makefile

The first method wraps the build steps in the second method to a single command, which is convenient but has a down side that it reduces the customization capability which the second method has. Therefor, pick the method which fits the use case.

Build U-Boot Using the SDK Top Level Makefile#

$ cd <SDK_INSTALL_DIR>/
$ make u-boot

Build U-Boot Using the U-Boot Top Level Makefile#

Once the Processor SDK Linux package is installed, the U-Boot source code is under <SDK_INSTALL_DIR>/board-support/ti-u-boot-<version>/. Please refer to Processor SDK Documentation U-Boot User Guide for how to compile the U-Boot for AM62Ax in the U-Boot source code directory.

Target Images#

The steps above will generate the following U-Boot images.

tiboot3.bin

Located under folder <SDK_INSTALL_DIR>/board-support/u-boot-build/r5. This is the first stage of the boot loader running on R5F core.

tispl.bin

Located under folder <SDK_INSTALL_DIR>/board-support/u-boot-build/a53/. This is the first stage of the boot loader running on A53 core.

u-boot.img

Located under folder <SDK_INSTALL_DIR>/board-support/u-boot-build/a53/. This is the second stage of the boot loader running on A53 core.

Update U-Boot on SD Card#

After the U-Boot images are generated, they can be copied to an SD card that has already been flashed with a bootable Linux image. The SD card has two partitions, boot and root. The U-Boot images should be copied to the boot partition. Insert the SD card into a card reader and plug the card reader into a Linux PC. Then, copy the U-Boot images to the card. Assuming that the SD card boot partition is mounted to /media/<username>/boot:

$ ls /media/<username>/boot
  tiboot3.bin  tispl.bin  uboot.env  u-boot.img  uEnv.txt
$ cd <SDK_INSTALL_DIR>/board-support/u-boot-build/
$ sudo cp r5/tiboot3.bin /media/<username>/boot/
$ sudo cp a53/tispl.bin /media/<username>/boot/
$ sudo cp a53/u-boot.img /media/<username>/boot/
$ sudo umount /media/<username>/boot

Now insert the SD card into the EVM. The EVM should boot with the updated U-Boot.