Build U-Boot from source code¶

Toolchain installation for out of builds¶

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

Build U-Boot out of tree¶

Obtain sources:

$ git clone https://github.com/varigit/uboot-imx -b lf_v2023.04_var02
$ cd uboot-imx

Configure compilation environment:

$ export ARCH=arm64
$ export CROSS_COMPILE=~/debian_imx8mp_var_dart/toolchain//bin/

Cleanup everything:

$ make mrproper

Select configuration:

$ make imx8mp_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-8.21.bin
$ chmod +x firmware-imx-8.21.bin
$ ./firmware-imx-8.21.bin
$ cp firmware-imx-8.21/firmware/ddr/synopsys/* .

Download and build ATF:

$ cp debian-var/variscite/imx8mp-var-dart/imx-boot-tools/bl31-imx8mp.bin bl31.bin

Download imx-mkimage:

$ git clone https://github.com/nxp-imx/imx-mkimage -b lf-6.1.36_2.1.0

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/imx8mp-var-dart-dt8mcustomboard.dtb ../arch/arm/dts/imx8mp-var-som-symphony.dtb .

Build boot image:

$ make -f soc.mak clean
$ make -f soc.mak  SOC=iMX8MP SOC_DIR=imx-boot-tools dtbs="imx8mp-var-dart-dt8mcustomboard.dtb  imx8mp-var-som-symphony.dtb"  MKIMG=./mkimage_imx8 PAD_IMAGE=./pad_image.sh  CC=gcc OUTIMG=imx-boot-sd.bin flash_evk

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/Debian

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 Debian tree¶

$ cd uboot-imx
$ git pull