Building with GCC¶
For building U-Boot you need a GCC compiler for your host platform. If you are not building on the target platform you further need a GCC cross compiler.
On Debian based systems the cross compiler packages are named gcc-<architecture>-linux-gnu.
You could install GCC and the GCC cross compiler for the ARMv8 architecture with
sudo apt-get install gcc gcc-aarch64-linux-gnu
Depending on the build targets further packages maybe needed
sudo apt-get install bc bison build-essential coccinelle \ device-tree-compiler dfu-util efitools flex gdisk liblz4-tool \ libguestfs-tools libncurses-dev libpython3-dev libsdl2-dev libssl-dev \ lzma-alone openssl python3 python3-coverage python3-pyelftools \ python3-pytest python3-sphinxcontrib.apidoc python3-sphinx-rtd-theme swig
On suse based systems the cross compiler packages are named cross-<architecture>-gcc<version>.
You could install GCC and the GCC 10 cross compiler for the ARMv8 architecture with
sudo zypper install gcc cross-aarch64-gcc10
Depending on the build targets further packages maybe needed.
zypper install bc bison flex gcc libopenssl-devel libSDL2-devel make \ ncurses-devel python3-devel python3-pytest swig
For some boards you have to build prerequisite files before you can build U-Boot, e.g. for the some boards you will need to build the ARM Trusted Firmware beforehand. Please, refer to the board specific documentation Board-specific doc.
Directory configs/ contains the template configuration files for the maintained boards following the naming scheme:
These files have been stripped of default settings. So you cannot use them directly. Instead their name serves as a make target to generate the actual configuration file .config. For instance the configuration template for the Odroid C2 board is called odroid-c2_defconfig. The corresponding .config file is generated by
You can adjust the configuration using
When cross compiling you will have to specify the prefix of the cross-compiler. You can either specify the value of the CROSS_COMPILE variable on the make command line or export it beforehand.
Assuming cross compiling on Debian for ARMv8 this would be
A list of available parameters for the make command can be obtained via
You can speed up compilation by parallelization using the -j parameter, e.g.
CROSS_COMPILE=aarch64-linux-gnu- make -j$(nproc)
Further important build parameters are
- O=<dir> - generate all output files in directory <dir>, including .config
- V=1 - verbose build
Other build targets¶
A list of all make targets can be obtained via
Important ones are
- clean - remove most generated files but keep the configuration
- mrproper - remove all generated files + config + various backup files