Customizing U-Boot¶

Introduction¶

This guide demonstrates how to patch and rebuild Debian U-Boot images.

To learn how to build the U-Boot images outside of Debian, see: Build U-Boot from source code

Prerequisites¶

Make sure you set up the FlexBuild Docker environment properly by following FlexBuild Setup and Usage.

Add your patches on top of the Variscite source code¶

The following steps can be executed outside or inside the container.

Fetch the U-Boot source:

git clone  -b lf_v2024.04_6.6.52-2.2.2_var01
cd uboot-imx
git clean -fdx

Next, make the desired changes to the U-Boot source code. Example:

vim drivers/net/fsl_enetc.c
vim drivers/net/fsl_enetc.h

After changing the source code, commit the changes locally and generate a patch file:

git add .
git commit -e
git format-patch -1

Once the patch is created, copy it to the U-Boot patch folder, which is inside the Flexbuild directory:

mkdir -p [...]/flexbuild/patch/uboot/
cp 0001-my-changes.patch [...]/flexbuild/patch/uboot/

Build U-Boot individually¶

Do not run any 'git am' or 'git apply' command. That will be done inside the U-Boot Makefile. Now, if you're not inside the container, get in with the following commands:

cd [...]/flexbuild           # (Outside Docker environment)
. setup.env                  # (Outside Docker environment)
bld docker                   # (Outside Docker environment)

Once you've entered the Docker environment, run:

bld -f sdk-var.yml -m imx8mq-var-dart uboot           # (Inside Docker environment)

Rebuild U-Boot¶

Once you've built U-Boot, a clean step is needed if a rebuild is required:

bld clean-bsp                                           # (Inside Docker environment)

Then, just build U-Boot normally with:

bld -f sdk-var.yml -m imx8mq-var-dart uboot           # (Inside Docker environment)