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 imx_v2020.04_5.4.70_2.3.0_var01
$ cd uboot-imx

Configure compilation environment:

$ source /opt/fslc-xwayland/3.3/environment-setup-cortexa53-crypto-fslc-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-8.10.bin
$ chmod +x firmware-imx-8.10.bin
$ ./firmware-imx-8.10.bin
$ cp firmware-imx-8.10/firmware/ddr/synopsys/* .

Download imx_mkimage:

$ git clone https://github.com/nxp-imx/imx-mkimage -b imx_5.4.70_2.3.0
$ 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 imx_5.4.70_2.3.0_var01 
$ git clone https://github.com/varigit/meta-variscite-fslc -b hardknott
$ cd imx-mkimage

$ git apply ../meta-variscite-fslc/recipes-bsp/imx-mkimage/imx-boot/imx-mkimage-imx8m-soc.mak-add-variscite-imx8mm-suppo.patch
$ rm *.patch
$ cp iMX8M/soc.mak ..
$ cd ..
$ cd imx-atf 
$ source /opt/fslc-xwayland/3.3/environment-setup-cortexa53-crypto-fslc-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  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-sd.bin /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