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 -b lf_v2023.04_var02
$ cd uboot-imx

Configure compilation environment:

$ source /opt/var-debian-xwayland/1.0/environment-setup-armv8a-fsl-linux

Cleanup everything:

$ make mrproper

Select configuration:

$ make imx93_var_som_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 Sentinel firmware:

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-sentinel-0.11.bin
$ chmod +x firmware-sentinel-0.11.bin
$ ./firmware-sentinel-0.11.bin
$ cp firmware-sentinel-0.11/mx93a1-ahab-container.img .

Download DDR firmware:

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.21.bin
$ chmod +x firmware-imx-8.21.bin
$ ./firmware-imx-8.21.bin
$ cp firmware-imx-8.21/firmware/ddr/synopsys/* .

Download and build imx_mkimage:

$ git clone https://github.com/nxp-imx/imx-mkimage -b lf-6.1.36_2.1.0
$ cd imx-mkimage
$ make soc=iMX9
$ cp iMX9/soc.mak mkimage_imx8 ..
$ cd ..

Download and build ATF:

$ git clone https://github.com/varigit/imx-atf -b lf_v2.8_var02 

$ cd imx-atf 
$ source /opt/var-debian-xwayland/1.0/environment-setup-armv8a-fsl-linux
$ unset LDFLAGS
$ make PLAT=imx93 bl31
$ cp build/imx93/release/bl31.bin ..
$ cd ..

Copy U-Boot binaries:

$ cp ../tools/mkimage mkimage_uboot
$ cp ../u-boot.bin .
$ cp ../spl/u-boot-spl.bin ../arch/arm/dts/imx93-var-som-symphony.dtb .

Build boot image:

$ make -f soc.mak clean
$ make -f soc.mak  SOC=iMX9  dtbs="imx93-var-som-symphony.dtb"  MKIMG=./imx-mkimage/mkimage_imx8 PAD_IMAGE=./pad_image.sh  CC=gcc flash_singleboot
$ mv flash.bin imx-boot-sd.bin

Install the built U-Boot on an SD card

$ sudo dd if=imx-boot-sd.bin of=/dev/sdX bs=1K seek=32 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