Documentation

The following links contain the “Product Brief,” “Datasheet,” and “User Manual.”

• Chip Product Documentation

Compiling Linux Firmware

Note:

1. Builds in a container by default. To build on the host machine, configure the environment variable export DIRECT_BUILD=1. When switching between container and host machine builds, you need to clean the output directory.

2. A new set of commands has been added. These are incompatible with older commands. To use the new commands, delete the env.mk file generated by the old commands in the project root directory. You can then use make help to view the list of new commands. For example, you can use make k3-build to directly compile a specified solution.

   $ cd ~/k3-buildroot-sdk-1.0
   $ rm -rf env.mk
   $ make help
   Buildroot Build System - Help
   
   Available solutions:
     aibox-k3 k3 k3_ci k3_fpga k3_plt
   
   Development Commands:
     make vars                          # Show project information
     make <solution>-supported          # Check if solution is supported
     make <solution>-config             # Apply solution defconfig
     make <solution>-menuconfig         # Configure buildroot for solution
     make <solution>-linux-menuconfig   # Configure Linux kernel for solution
     make <solution>-uboot-menuconfig   # Configure U-Boot for solution
     make <solution>-busybox-menuconfig # Configure BusyBox for solution
     make <solution>-build              # Build specified solution
     make <solution>-pkg PKG=<package>  # Build specified package for solution
     make <solution>-shell              # Enter build container for solution
     make <solution>-source             # Download all source packages for solution
     make <solution>-clean              # Clean solution build artifacts
     make <solution>-cleanbuild         # Clean and rebuild solution
     make build-docker-image            # Build Docker image
     make update-docker-image           # Update Docker image
   
   Quick Start: Run 'make <solution>-build' to get started, e.g.:
     make k3-build
   

Compiling Buildroot Firmware

Pre-compilation Configuration

$ cd ~/k3-buildroot-sdk-1.0
$ make envconfig
Available configs in /home2/lvsx/ext/project/k3/buildroot-ext/configs:
  1. spacemit_aibox-k3_defconfig
  2. spacemit_k3_ci_defconfig
  3. spacemit_k3_defconfig
  4. spacemit_k3_fpga_defconfig
  5. spacemit_k3_plt_defconfig

Your choice (1-5):

Enter 1 here and select spacemit_aibox-k3_defconfig.

The compilation process may require downloading some third-party packages; the exact time depends on your network environment. If you download the third-party packages that buildroot depends on beforehand, the recommended compilation time is approximately 1 hour based on your hardware configuration.

The compilation output is located in the /output/k3/images/ directory. A successful compilation and packaging log is shown below:

Generating sdcard image...................................
INFO: cmd: "mkdir -p "/aibox-k3/build/genimage.tmp"" (stderr):
INFO: cmd: "rm -rf "/aibox-k3/build/genimage.tmp"/*" (stderr):
INFO: cmd: "mkdir -p "/aibox-k3/images"" (stderr):
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'env' from 'env.bin' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'bootinfo' from 'factory/bootinfo_block.bin' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'fsbl' from 'factory/FSBL.bin' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'esos' from 'esos.itb' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'opensbi' from 'fw_dynamic.itb' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'uboot' from 'u-boot.itb' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'bootfs' (in MBR) from 'bootfs.img' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition 'rootfs' (in MBR) from 'rootfs.ext4' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition '[MBR]' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition '[GPT header]' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition '[GPT array]' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): adding primary partition '[GPT backup]' ...
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): writing GPT
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): writing protective MBR
INFO: hdimage(Buildroot-aibox-k3-20260508163419-sdcard.img): writing MBR
INFO: cmd: "rm -rf "/aibox-k3/build/genimage.tmp/"" (stderr):
Successfully generated at /aibox-k3/images/Buildroot-aibox-k3-20260508163419-sdcard.img

The Buildroot-K3-xxx.zip file is suitable for Titan Flasher, or can be unzipped and flashed using fastboot; Buildroot-K3-xxx-sdcard.img is the SD card firmware, which can be written to the SD card using the dd command or balenaEtcher after unzipping.

The default username for the firmware is root, and the password is firefly.

Compiling Bianbu Firmware

Preparation

Download the root filesystem: Bianbu Root Filesystem (64-bit)

After downloading, extract the filesystem to SDK/buildroot-ext/board/spacemit/k3/ and rename it.

7z x Bianbu-Lxqt_rootfs_xxx.7z

# Move the extracted rootfs image to the specified directory in the SDK. The name must be rootfs.ext4.
mv Bianbu-Lxqt_rootfs_xxx.ext4 /SDK/buildroot-ext/board/spacemit/k3/rootfs.ext4

Pre-compilation configuration

$ cd ~/k3-buildroot-sdk-1.0
$ make envconfig
Available configs in /home2/lvsx/ext/project/k3/buildroot-ext/configs:
  1. spacemit_aibox-k3_defconfig
  2. spacemit_k3_ci_defconfig
  3. spacemit_k3_defconfig
  4. spacemit_k3_fpga_defconfig
  5. spacemit_k3_plt_defconfig

Your choice (1-5):

Enter 1 here and select spacemit_aibox-k3_defconfig.

The compilation process will replace the buildroot file system with the /SDK/buildroot-ext/board/spacemit/k3/rootfs.ext4 file system.

Configuration

Configuration requires entering the Docker build environment.

make aibox-k3-shell

buildroot

Configuration:

make menuconfig

The configuration is saved to buildroot-ext/configs/spacemit_aibox-k3_defconfig by default.

make savedefconfig

Linux

Configuration:

make linux-menuconfig

Save the configuration, which by default is saved to bsp-src/linux-6.18/arch/riscv/configs/k3_bianbu_defconfig:

make linux-update-defconfig

u-boot

Configuration:

make uboot-menuconfig

Save the configuration, which by default is saved to bsp-src/uboot-2022.10/configs/k3_defconfig:

make uboot-update-defconfig

Recompile Completely

If you have already compiled completely using make envconfig, you can directly use make to compile completely again.

Compile a Specific Package

Buildroot supports compiling a specific package. You can use make help to view the guide.

Common Commands:

• Delete the compilation directory of <pkg>: make <pkg>-dirclean

• Compile <pkg>: make <pkg>

• Recompile <pkg>: make <pkg>-rebuild

u-boot

#Compilation
make uboot

#Cleanup
make uboot-dirclean

#Recompile
make uboot-rebuild

Linux

The kernel’s default configuration is k3_bianbu_defconfig

#Compilation
make linux

#Cleanup
make linux-dirclean

#Recompile
make linux-rebuild

opensbi

#Compilation
make opensbi

#Cleanup
make opensbi-dirclean

#Recompile
make opensbi-rebuild

After compiling the specified package, it can be downloaded separately to the device for verification, or compiled into the firmware:

make