Yocto Build U-Boot

From Variscite Wiki
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_v2022.04_var02
$ cd uboot-imx

Configure compilation environment:

$ source /opt/fsl-imx-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-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-0.8.bin
$ chmod +x firmware-sentinel-0.8.bin
$ ./firmware-sentinel-0.8.bin
$ cp firmware-sentinel-0.8/mx93a0-ahab-container.img .

Download DDR firmware:

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.18.bin
$ chmod +x firmware-imx-8.18.bin
$ ./firmware-imx-8.18.bin
$ cp firmware-imx-8.18/firmware/ddr/synopsys/* .

Download and build imx_mkimage:

$ git clone https://github.com/nxp-imx/imx-mkimage -b lf-5.15.71_2.2.0
$ cd imx-mkimage
$ make soc=iMX9
$ cp iMX9/soc.mak mkimage_imx8 ..
$ cd ..

Download and build ATF:

$ git clone https://github.com/nxp-imx/imx-atf -b lf_v2.6 

$ cd imx-atf 
$ source /opt/fsl-imx-xwayland/5.15-kirkstone/environment-setup-armv8a-poky-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-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