Buildroot

Source: AMD Adaptive Computing Wiki – Buildroot

This page highlights AMD support for Buildroot as an alternative community Linux solution to Yocto. Unofficial support for AMD architectures (Zynq, Zynq MPSoC, Kria SOMs and Versal Adaptive SoC) are available. The Buildroot configs directory provides a number of example defconfig files for common evaluation boards which use AMD devices.

Buildroot is not WTS supported and should only be used by experienced users. However, Buildroot does use the same supported software as Yocto from the https://www.github.com/Xilinx repository. Any issues with this underlying software which can be duplicated using Yocto or Vitis are supported by WTS. But any issues with configuring Buildroot for custom hardware should be addressed to the Buildroot community.

One exception to the above is the Zynq and Zynq MPSoC U-Boot Secondary Program Loader (SPL). While it is included with U-Boot and Buildroot, the WTS supported flow for the Zynq and Zynq MPSoC families is the First Stage Bootloader (FSBL). Experienced users are welcome to give the U-Boot SPL a try as it is documented here. However, if technical support is needed, the Xilinx recommendation is to build the boot.bin using the FSBL and bootgen. It is possible to use Yocto or Vitis for building a hardware specific boot.bin while still using Buildroot for building the Linux kernel and file system.

General Information

Official Buildroot release activity and version information can be found at:

Releases - Buildroot

The following table correlates Buildroot LTS releases to the corresponding AMD releases.

AMD Release Tag	Buildroot LTS Release	Linux Kernel LTS
`xilinx_v2024.2`	`2025.02`	`6.6`
`xilinx_v2023.2`	`2024.02`	`6.1`
`xilinx_v2022.2`	`2023.02`	`5.15`

Starting with the 2025.02 release, Buildroot LTS releases are maintained for 3 years and every other year will have an LTS release. Because Buildroot LTS releases happen in February, they will always be based on the prior year’s AMD Adaptive .2 release. For example, Buildroot 2025.02 is based on the xilinx_v2024.2 AMD release.

To test the latest AMD release before the next Buildroot February LTS release, it is possible to clone the Buildroot master branch which already includes the latest AMD release.

git clone https://gitlab.com/buildroot.org/buildroot.git

Supported AMD Evaluation Boards

Zynq

Zynq UltraScale+

Kria SOM

.## Versal

Versal Gen 2

versal2_vek385_defconfig

Getting Started with Buildroot

This page provides a step-by-step guide to configuring Buildroot to generate an embedded Linux system using the AMD Linux release. Now that many defconfig examples have been added to Buildroot mainline, the latest AMD software will build and run on a variety of evaluation boards with very little effort.

Host System Requirements

Buildroot documents the requirements for the host Linux development machine here:

Buildroot Manual

Build Steps

1. Download the Latest LTS Version of Buildroot

Buildroot - Making Embedded Linux Easy

2. Review the Buildroot Directory Structure

Buildroot includes a well-organized directory structure documented in the official documentation.

3. Inspect the Following Directories

`configs`

Contains build examples for AMD evaluation boards that can be used as templates for creating custom target board configurations.

`board`

Contains a readme.txt file and open-source build scripts for each AMD evaluation board family.

The post-image.sh script operates on the genimage.cfg file for creation of the SD card image for booting.

Example board directories:

board/zynq
board/zynqmp
board/zynqmp/kria
board/versal
board/versal2

4. Configure Buildroot for an AMD Evaluation Board

Example for the AMD ZCU102:

make zynqmp_zcu102_defconfig

5. Build the Target Images

make

6. Inspect the Output Directories

`output/build`

Contains the sources of all packages that were built.

`output/images`

Contains all target images that will run on the target board, including sdcard.img.

Example layout:

output/images/
+-- atf-uboot.ub
+-- bl31.bin
+-- boot.bin
+-- boot.vfat
+-- Image
+-- rootfs.ext2
+-- rootfs.ext4 -> rootfs.ext2
+-- sdcard.img
+-- system.dtb -> zynqmp-zcu102-rev1.0.dtb
+-- u-boot.itb
`-- zynqmp-zcu102-rev1.0.dtb

7. Image the SD Card for Booting

dd if=output/images/sdcard.img of=/dev/sdX

Where sdX is the device node of the SD card on the host.

8. Configure the Target Evaluation Board for SD Card Boot Mode

Set the board boot switches appropriately for SD card boot.

9. Login Credentials

Default root password:

root

Example login:

Welcome to Buildroot
buildroot login:

Buildroot Custom Hardware Device Tree

Buildroot expects custom hardware specifications to already be in Device Tree format. To create a device tree for custom hardware, it is recommended to use the supported Software Hardware Exchange Loop which is the same flow used by Yocto.

ZCU102 Example with Custom PL Bitstream

1. SDTGen

Convert Vivado XSA file (system.xsa) to system device tree files.

sdtgen -xsa zcu102.xsa -dir sdt_out -board_dts zynqmp-zcu102-rev1.0

2. Lopper

Strip out zynqmp_linux.dts and pl.dtsi files from system device tree files.

export LOPPER_DTC_FLAGS="-b 0 -@"
git clone -b xilinx_v2025.2 https://github.com/Xilinx/lopper.git
mkdir -p ./lopper_out
lopper -f --enhanced ./sdt_out/system-top.dts ./lopper_out/system.dts -- xlnx_overlay_dt cortexa53-zynqmp full
lopper -f --enhanced -O ./lopper_out -i ./lopper/lopper/lops/lop-a53-imux.dts ./lopper_out/system.dts zynqmp_linux.dts -- gen_domain_dts psu_cortexa53_0 linux_dt

3. Buildroot

Change zynqmp_zcu102_defconfig to use the Lopper-generated zynqmp_linux.dts instead of the in-tree DTS.

4. Create External DTS Directory

mkdir -p ./buildroot_dts
mkdir -p ./buildroot_dts/xilinx
cp ./lopper_out/zynqmp_linux.dts ./buildroot_dts/xilinx

5. Modify Buildroot Defconfig

Modify:

<buildroot_dir>/configs/zynqmp_zcu102_defconfig

Add or update:

+BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="./buildroot_dts"
-BR2_LINUX_KERNEL_INTREE_DTS_NAME="xilinx/zynqmp-zcu102-rev1.0"

6. Rebuild Buildroot

make

7. Image the SD Card

dd if=output/images/sdcard.img of=/dev/sdX

Where sdX is the device node of the SD card on the host.

8. Boot the Board from SD Card

Configure the ZCU102 boot mode switches for SD card boot and power on the board. Login as root.

root

Welcome to Buildroot
buildroot login:

9. Load the FPGA Bitstream at Runtime

After Linux boots, load the FPGA bitstream using fpgautil:

fpgautil -b /lib/firmware/xilinx/zcu102.bit.bin -o /lib/firmware/xilinx/pl.dtbo

VEK280 Example with Custom pld.pdi

1. SDTGen

sdtgen -xsa vek280.xsa -dir sdt_out -board_dts versal-vek280-revb

2. Lopper

export LOPPER_DTC_FLAGS="-b 0 -@"
git clone -b xilinx_v2025.2 https://github.com/Xilinx/lopper.git
mkdir -p ./lopper_out
lopper -f --enhanced ./sdt_out/system-top.dts ./lopper_out/system.dts -- xlnx_overlay_dt cortexa72-versal full
lopper -f --enhanced -O ./lopper_out -i ./lopper/lopper/lops/lop-a72-imux.dts ./lopper_out/system.dts versal_linux.dts -- gen_domain_dts psv_cortexa72_0 linux_dt

3. Buildroot

Change versal_vek280_defconfig to use the Lopper-generated versal_linux.dts.

4. Create External DTS Directory

mkdir -p ./buildroot_dts
mkdir -p ./buildroot_dts/xilinx
cp ./lopper_out/versal_linux.dts ./buildroot_dts/xilinx

5. Modify Buildroot Defconfig

Modify:

<buildroot_dir>/configs/versal_vek280_defconfig

Update:

+BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="./buildroot_dts"
-BR2_LINUX_KERNEL_INTREE_DTS_NAME="xilinx/versal-vek280-revB"

6. Rebuild Buildroot

make

7. Image the SD Card

dd if=output/images/sdcard.img of=/dev/sdX

Where sdX is the device node of the SD card on the host.

8. Boot the Board from SD Card

Configure the VEK280 boot mode switches for SD card boot and power on the board. Login as root.

root

Welcome to Buildroot
buildroot login:

9. Load the PLD Image at Runtime

After Linux boots, load the programmable logic image using fpgautil:

fpgautil -b /lib/firmware/xilinx/vek280_pld.pdi -o /lib/firmware/xilinx/pl.dtbo

VEK385 Example with Custom pld.pdi

1. SDTGen

sdtgen -xsa vek385.xsa -dir sdt_out -board_dts versal2-vek385-revb

2. Lopper

export LOPPER_DTC_FLAGS="-b 0 -@"
git clone -b xilinx_v2025.2 https://github.com/Xilinx/lopper.git
mkdir -p ./lopper_out
lopper -f --enhanced ./sdt_out/system-top.dts ./lopper_out/system.dts -- xlnx_overlay_dt cortexa78-versal2 full
lopper -f --enhanced -O ./lopper_out -i ./lopper/lopper/lops/lop-a78-imux.dts ./lopper_out/system.dts versal2_linux.dts -- gen_domain_dts cortexa78_0 linux_dt

3. Buildroot

Change versal2_vek385_defconfig to use the Lopper-generated versal2_linux.dts.

4. Create External DTS Directory

mkdir -p ./buildroot_dts
mkdir -p ./buildroot_dts/xilinx
cp ./lopper_out/versal2_linux.dts ./buildroot_dts/xilinx

5. Modify Buildroot Defconfig

Modify:

<buildroot_dir>/configs/versal2_vek385_defconfig

Update:

+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="./buildroot_dts"

6. Rebuild Buildroot

make

7. Image the SD Card

dd if=output/images/sdcard.img of=/dev/sdX

Where sdX is the device node of the SD card on the host.

8. Boot the Board from SD Card

Configure the VEK385 boot mode switches for SD card boot and power on the board. Login as root.

root

Welcome to Buildroot
buildroot login:

9. Load the PLD Image at Runtime

After Linux boots, load the programmable logic image using fpgautil:

fpgautil -b /lib/firmware/xilinx/vek385_pld.pdi -o /lib/firmware/xilinx/pl.dtbo

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Buildroot

Table of Contents

General Information

Supported AMD Evaluation Boards

Zynq

Zynq UltraScale+

Kria SOM

Versal Gen 2

Getting Started with Buildroot

Host System Requirements

Build Steps

1. Download the Latest LTS Version of Buildroot

2. Review the Buildroot Directory Structure

3. Inspect the Following Directories

configs

board

4. Configure Buildroot for an AMD Evaluation Board

5. Build the Target Images

6. Inspect the Output Directories

output/build

output/images

7. Image the SD Card for Booting

8. Configure the Target Evaluation Board for SD Card Boot Mode

9. Login Credentials

Buildroot Custom Hardware Device Tree

ZCU102 Example with Custom PL Bitstream

1. SDTGen

2. Lopper

3. Buildroot

4. Create External DTS Directory

5. Modify Buildroot Defconfig

6. Rebuild Buildroot

7. Image the SD Card

8. Boot the Board from SD Card

9. Load the FPGA Bitstream at Runtime

VEK280 Example with Custom pld.pdi

1. SDTGen

2. Lopper

3. Buildroot

4. Create External DTS Directory

5. Modify Buildroot Defconfig

6. Rebuild Buildroot

7. Image the SD Card

8. Boot the Board from SD Card

9. Load the PLD Image at Runtime

VEK385 Example with Custom pld.pdi

1. SDTGen

2. Lopper

3. Buildroot

4. Create External DTS Directory

5. Modify Buildroot Defconfig

6. Rebuild Buildroot

7. Image the SD Card

8. Boot the Board from SD Card

9. Load the PLD Image at Runtime

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`configs`

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