Yocto Customizing U-Boot

From Variscite Wiki
DART-MX8M-MINI - Customizing U-Boot


Choose one of the following three methods to customize U-Boot.
After following one of the below methods, you may use the updated U-Boot by either building your complete image (e.g. fsl-image-gui) or building a new imx-boot image by running "bitbake imx-boot -c deploy" (see the Build Boot2Qt from source code page for the initial setup and for more info on using bitbake).
To install the new imx-boot image (with the updated U-Boot) to an SD Card, run:

$ sudo dd if=tmp/deploy/images/imx8mm-var-dart/imx-boot of=/dev/sdX bs=1K seek=33 conv=fsync

1 Add your own patches on top of our source code

Using this method Yocto will take the source code from our default remote repository, and apply your patches to it before building it:

Setup Yocto:

  • Follow steps 1-3 of the Build Boot2Qt from source code page.
  • Follow the first part of step 4 of the same page, to source the setup-environment script (stop after that - don't build any image). E.g.:
$ cd ~/var-b2qt
$ MACHINE=imx8mm-var-dart  . setup-environment.sh 


Get the source code:

$ MACHINE=imx8mm-var-dart bitbake -c unpack virtual/bootloader
$ mkdir -p ../local_repos/uboot-imx
$ cp -a tmp/work/imx8mm_var_dart-fslc-linux/u-boot-variscite/1.0-r0/git/. ../local_repos/uboot-imx
$ cd ../local_repos/uboot-imx
$ git reset --hard
$ git clean -fdx


Make your changes in the source code and create a patch:
You can use either diff or patch file types.
For example:

$ cd ~/var-b2qt/local_repos/uboot-imx
$ gedit board/variscite/imx8mm_var_dart/imx8mm_var_dart.c
$ gedit include/configs/imx8mm_var_dart.h
edit and save

$ git diff > my_imx8mm_var_dart_changes.diff


Update the recipes to use your patch:

Copy your patch:

$ cd ~/var-b2qt/sources/meta-variscite-bsp/recipes-bsp/u-boot/
$ mkdir -p files
$ cp ~/var-b2qt/local_repos/uboot-imx/my_imx8mm_var_dart_changes.diff  files/

Create a u-boot-variscite.bbappend file:

$ gedit u-boot-variscite.bbappend

and append the following line to it:

SRC_URI += "file://my_imx8mm_var_dart_changes.diff"


2 Use a local repository

Using this method Yocto will take the U-Boot source from a local repository instead of our remote ones on github:

Setup Yocto:

  • Follow steps 1-3 of the Build Boot2Qt from source code page.
  • Follow the first part of step 4 of the same page, to source the setup-environment script (stop after that - don't build any image). E.g.:
$ cd ~/var-b2qt
$ MACHINE=imx8mm-var-dart  . setup-environment.sh 


Get the source code:

$ MACHINE=imx8mm-var-dart bitbake -c unpack virtual/bootloader
$ mkdir -p ../local_repos/uboot-imx
$ cp -a tmp/work/imx8mm_var_dart-fslc-linux/u-boot-variscite/1.0-r0/git/. ../local_repos/uboot-imx
$ cd ../local_repos/uboot-imx
$ git reset --hard
$ git clean -fdx


Make your changes in the source code and commit them:
After making changes in the source code you need to commit them.
For example:

$ cd ~/var-b2qt/local_repos/uboot-imx
$ gedit board/variscite/imx8mm_var_dart/imx8mm_var_dart.c
$ gedit include/configs/imx8mm_var_dart.h
edit and save

$ git commit -a -m "my_imx8mm_var_dart_changes"
To list all of the commits:
$ git log
Get the latest commit id:
$ git rev-parse HEAD


Update the recipes to use the local repository instead of the default one:

$ cd ~/var-b2qt/sources/meta-variscite-bsp/recipes-bsp/u-boot/

Create a u-boot-variscite.bbappend file:

$ gedit u-boot-variscite.bbappend

and append the following lines to it (see the previous section for listing the commits or getting the latest commit id):

UBOOT_SRC = "git://${BSPDIR}/local_repos/uboot-imx;protocol=file"
SRCBRANCH = "lf_v2021.04_var03" (or your own created branch)
SRCREV = "The commit id you'd like to use"



For the SRCREV value you can also use "${AUTOREV}" during development to get the latest commit of the branch
(If you do so, make sure to run "MACHINE=imx8mm-var-dart bitbake -c cleansstate virtual/bootloader" before rebuilding U-Boot)

3 Use your own remote repository on github

Using this method Yocto will take the source code from your own remote repository on github:

Create your own github account and upload your proprietary U-Boot to a new repository:
For example, you can fork our repository to your own account by visiting the following link and clicking on "Fork" at the top right of the screen.
Alternatively, you can clone our repository to your local machine, and push it later to your own account.

https://github.com/varigit/uboot-imx/tree/lf_v2021.04_var03


Update the recipes to use your remote repository instead of the default one:

$ cd ~/var-b2qt/sources/meta-variscite-bsp/recipes-bsp/u-boot/

Create a u-boot-variscite.bbappend file:

$ gedit u-boot-variscite.bbappend

and append the following lines to it (see the previous section for listing the commits or getting the latest commit id):

UBOOT_SRC = "git://github.com/your_account/uboot-imx.git;protocol=git"
SRCBRANCH = "lf_v2021.04_var03" (or your own created branch)
SRCREV = "The commit id you'd like to use"



For the SRCREV value you can also use "${AUTOREV}" during development to get the latest commit of the branch
(If you do so, make sure to run "MACHINE=imx8mm-var-dart bitbake -c cleansstate virtual/bootloader" before rebuilding U-Boot)