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_v2025.04_6.12.49-2.2.0_var01
$ cd uboot-imx
Configure compilation environment:
Cleanup everything:
Select configuration:
Build U-Boot:
Download and install Arm-none-eabi cross-compiler required to build OEI and SM
$ wget https://developer.arm.com/-/media/Files/downloads/gnu/14.2.rel1/binrel/arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi.tar.xz
$ sudo tar -xf arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi.tar.xz -C /opt
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:
Download imx_mkimage:
Download DDR firmware:
$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.30-3fa84fd.bin
$ chmod +x firmware-imx-8.30-3fa84fd.bin
$ ./firmware-imx-8.30-3fa84fd.bin
$ rm firmware-imx-8.30-3fa84fd.bin
$ cp firmware-imx-8.30-3fa84fd/firmware/ddr/synopsys/* imx-mkimage/iMX95
Download ELE firmware:
$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-ele-imx-2.0.4-93492e0.bin
$ chmod +x firmware-ele-imx-2.0.4-93492e0.bin
$ ./firmware-ele-imx-2.0.4-93492e0.bin
$ rm firmware-ele-imx-2.0.4-93492e0.bin
$ cp firmware-ele-imx-2.0.4-93492e0/mx95b0-ahab-container.img imx-mkimage/iMX95
Download and build ATF:
$ git clone https://github.com/varigit/imx-atf -b lf_v2.12_6.12.49-2.2.0_var01
$ cd imx-atf
$ source /opt/fsl-imx-xwayland/6.12-walnascar/environment-setup-armv8a-poky-linux
$ unset CFLAGS
$ unset LDFLAGS
$ unset AS
$ unset LD
$ make PLAT=imx95 bl31
$ cp build/imx95/release/bl31.bin ../imx-mkimage/iMX95
$ cd ..
Download and build OEI DDR Image and OEI TCM Image:
$ git clone https://github.com/varigit/imx-oei -b lf-6.12.49-2.2.0_var01
$ cd imx-oei
$ export OEI_CROSS_COMPILE=/opt/arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-
$ make really-clean
$ make board=mx95-var-dart DEBUG=1 DDR_CONFIG=lpddr5_8gb_6400mbps_train_timing r=B0 oei=ddr
$ cp build/mx95-var-dart/ddr/oei-m33-ddr.bin ../imx-mkimage/iMX95
$ make board=mx95-var-dart DEBUG=0 DDR_CONFIG=lpddr5_8gb_6400mbps_train_timing r=B0 oei=tcm
$ cp build/mx95-var-dart/tcm/oei-m33-tcm.bin ../imx-mkimage/iMX95
$ cd ..
Note: OEI must currently be compiled specifically for the supported RAM size of your DART-MX95 module.
Depending on your SOM’s RAM configuration, the DDR_CONFIG variable must be set accordingly:
- DART-MX95 4GB:
lpddr5_4gb_6400mbps_train_timing - DART-MX95 8GB:
lpddr5_8gb_6400mbps_train_timing - DART-MX95 16GB:
lpddr5_16gb_6400mbps_train_timing
The default configuration is lpddr5_8gb_6400mbps_train_timing, as shown above.
Download and build SM:
$ git clone https://github.com/varigit/imx-sm -b lf-6.12.49-2.2.0_var01
$ cd imx-sm
$ export SM_CROSS_COMPILE=/opt/arm-gnu-toolchain-14.2.rel1-x86_64-arm-none-eabi/bin/arm-none-eabi-
$ make really-clean
$ make -j $(nproc --all) config=dart-mx95 cfg
$ make -j $(nproc --all) config=dart-mx95 img
$ cp build/dart-mx95/m33_image.bin ../imx-mkimage/iMX95
$ cd ..
Copy U-Boot binaries:
Build boot image:
$ cd imx-mkimage
$ make clean
$ make SOC=iMX95 flash_a55 REV=B0 OEI=YES LPDDR_TYPE=lpddr5 LPDDR_FUNC=train
$ mv iMX95/flash.bin iMX95/imx-boot-sd.bin
Install the built U-Boot on an SD card¶
$ sudo dd if=iMX95/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:
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)