Yocto Build U-Boot from source code

Toolchain installation for out of Yocto builds

To install the toolchain, follow the Yocto Toolchain installation guide.

Build U-Boot out of Yocto tree

Obtain sources:

$ git clone https://github.com/varigit/uboot-imx.git -b lf_v2023.04_var01
$ cd uboot-imx

Configure compilation environment:

$ source /opt/fsl-imx-xwayland/6.1-mickledore/environment-setup-armv8a-poky-linux

Cleanup everything:

$ make mrproper

Select configuration:

$ make imx8mm_var_dart_defconfig

Build U-Boot:

$ make -j$(nproc)

Build boot image

The final boot image contains multiple firmware files, as explained by NXP in IMX_LINUX_USERS_GUIDE.pdf (Search for "How to build imx-boot image by using imx-mkimage").

The following procedure builds the final image:

Create imx-boot-tools directory:

$ mkdir imx-boot-tools
$ cd imx-boot-tools

Download DDR firmware:

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.20.bin
$ chmod +x firmware-imx-8.20.bin
$ ./firmware-imx-8.20.bin
$ cp firmware-imx-8.20/firmware/ddr/synopsys/* .

Download imx_mkimage:

$ git clone https://github.com/nxp-imx/imx-mkimage -b lf-6.1.22_2.0.0
$ cp imx-mkimage/iMX8M/*.c imx-mkimage/iMX8M/*.sh  imx-mkimage/scripts/*.sh .
$ cp dtb_check.sh ../scripts/

Download and build ATF:

$ git clone https://github.com/varigit/imx-atf -b lf_v2.8_var01 
$ git clone https://github.com/varigit/meta-variscite-bsp-imx -b mickledore-var01
$ cd imx-mkimage
$ wget 'https://raw.githubusercontent.com/nxp-imx/meta-imx/mickledore-6.1.22-2.0.0/meta-bsp/recipes-bsp/imx-mkimage/files/0001-iMX8M-soc.mak-use-native-mkimage-from-sysroot.patch'
$ git apply 0001-iMX8M-soc.mak-use-native-mkimage-from-sysroot.patch
$ git apply ../meta-variscite-bsp-imx/recipes-bsp/imx-mkimage/imx-boot/0001-iMX8M-soc-allow-dtb-override.patch
$ git apply ../meta-variscite-bsp-imx/recipes-bsp/imx-mkimage/imx-boot/0002-iMX8M-soc-change-padding-of-DDR4-and-LPDDR4-DMEM-fir.patch
$ git apply ../meta-variscite-bsp-imx/recipes-bsp/imx-mkimage/imx-boot/0003-iMX8M-soc-add-variscite-imx8mm-support.patch
$ rm *.patch
$ cp iMX8M/soc.mak ..
$ cd ..
$ cd imx-atf 
$ source /opt/fsl-imx-xwayland/6.1-mickledore/environment-setup-armv8a-poky-linux
$ unset LDFLAGS
$ make PLAT=imx8mm bl31
$ cp build/imx8mm/release/bl31.bin ..
$ cd ..

Copy U-Boot binaries:

$ cp ../tools/mkimage mkimage_uboot
$ cp ../u-boot.bin .
$ cp ../u-boot-nodtb.bin ../spl/u-boot-spl.bin ../arch/arm/dts/imx8mm-var-dart-customboard.dtb ../arch/arm/dts/imx8mm-var-som-symphony.dtb  .

Build boot image:

$ make -f soc.mak clean
$ make -f soc.mak SOC=iMX8MM SOC_DIR=imx-boot-tools dtbs="imx8mm-var-dart-customboard.dtb imx8mm-var-som-symphony.dtb " MKIMG=./mkimage_imx8 PAD_IMAGE=./pad_image.sh CC=gcc OUTIMG=imx-boot-sd.bin flash_lpddr4_ddr4_evk

Install the built U-Boot on an SD card

$ sudo dd if=imx-boot-sd.bin of=/dev/sdX bs=1K seek=33 conv=fsync

(Replace /dev/sdX with the correct device)

If you want to use our recovery SD card to flash the built U-Boot to NAND flash/eMMC, then copy it to the appropriate location in the SD card:

$ sudo cp imx-boot /media/rootfs/opt/images/…

And eject the SD card gracefully from host machine.

Note: If you manually upgrade an existing U-Boot, and you have an old environment saved, it is a good idea to reset your environment to the new default (see Environment handling commands)

Update your U-Boot out of Yocto tree

$ git pull