# PYNQ image v3.1 for Pynq-Z1: build fails during RootFS (multistrap ubuntu-keyring error) **URL:** \ **Category:** Support\ **Created:** [August 15, 2025, 11:36am UTC](https://discuss.pynq.io/t/pynq-image-v3-1-for-pynq-z1-build-fails-during-rootfs-multistrap-ubuntu-keyring-error/8691 "2025-08-15T11:36:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Charlie\_FPGA](https://avatars.discourse-cdn.com/v4/letter/c/5daacb/32.png) [@Charlie\_FPGA](https://discuss.pynq.io/u/Charlie_FPGA)\ **Post date:** [August 15, 2025, 11:36am UTC](https://discuss.pynq.io/t/pynq-image-v3-1-for-pynq-z1-build-fails-during-rootfs-multistrap-ubuntu-keyring-error/8691/1 "2025-08-15T11:36:41Z")
Hi all, I’m trying to generate a **PYNQ image v3.1** for the **Pynq-Z1** using Docker. In the future I’ll target a different custom board. I followed this tutorial: [https://pynq.readthedocs.io/en/latest/pynq\_sd\_card.html](https://pynq.readthedocs.io/en/latest/pynq_sd_card.html) ## Host setup - Host: **WSL Ubuntu 22.04 LTS** - Tools installed: **Vitis, Vivado, Petalinux 2024.1** ## Docker: build and run Repository and build: ```bash git clone --recursive https://github.com/Xilinx/PYNQ.git PYNQ cd PYNQ/sdbuild docker build \ --build-arg USERNAME=$(whoami) \ --build-arg USER_UID=$(id -u) \ --build-arg USER_GID=$(id -g) \ -t pynqdock:latest . ``` Run container: ```bash docker run --init --rm -it \ -v /tools/Xilinx:/tools/Xilinx \ -v /home/xilinx/petalinux_projects:/home/xilinx/petalinux_projects \ --name pynq-sdbuild-env \ --privileged pynqdock:latest /bin/bash ``` ## Build output (hardware/XSA) ```plaintext INFO: [Project 1-1941] Successfully created Hardware Platform: /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_bsp/hardware_project/pynqz1.xsa INFO: [Hsi 55-2053] elapsed time for repository (/tools/Xilinx/Vivado/2024.1/data/embeddedsw) loading 0 seconds INFO: [Vivado 12-12082] Found metadata file: xsa.json INFO: [Vivado 12-6078] Validating platform properties... INFO: [Vivado 12-6079] Validating unified platform... INFO: [Vivado 12-6073] Validating 'pre_synth' platform state... INFO: [Vivado 12-6077] Validating platform files... INFO: [Vivado 12-6066] Finished running validate_hw_platform for file: './pynqz1.xsa' INFO: [Common 17-206] Exiting Vivado at Mon Aug 11 09:59:05 2025... Built pynqz1 successfully! ``` ## Build output (boot image) ```plaintext [INFO] Successfully built bootloader cd /home/xilinx/petalinux_projects/PYNQ/sdbuild/output/boot/Pynq-Z1 && petalinux-package --boot --fpga /home/xilinx/petalinux_projects/PYNQ/sdbuild/../boards/Pynq-Z1/base/base.bit --u-boot -p /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project --force [NOTE] Argument: "--boot" has been deprecated. It is recommended to start using new python command line Argument. [NOTE] Use: petalinux-package boot [OPTIONS] [INFO] File in BOOT BIN: "/home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project/images/linux/zynq_fsbl.elf" [INFO] File in BOOT BIN: "/home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project/images/linux/u-boot.elf" [INFO] File in BOOT BIN: "/home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project/images/linux/system.dtb" [INFO] Generating zynq binary package BOOT.BIN... [INFO] ****** Bootgen v2024.1 **** Build date : Apr 29 2024-12:18:25 ** Copyright 1986-2022 Xilinx, Inc. All Rights Reserved. ** Copyright 2022-2024 Advanced Micro Devices, Inc. All Rights Reserved. [INFO] : Bootimage generated successfully ``` ## Failure during RootFS generation At some point (I believe during RootFS generation), it fails: ```plaintext cp -f /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project/images/linux/BOOT.BIN /home/xilinx/petalinux_projects/PYNQ/sdbuild/output/boot/Pynq-Z1 PYNQ_BOARDNAME=Pynq-Z1 FPGA_MANAGER=1 petalinux-build -c u-boot-xlnx-scr -p /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project [INFO] Building u-boot-xlnx-scr ... NOTE: Tasks Summary: Attempted 789 tasks of which 771 didn't need to be rerun and all succeeded. [INFO] Failed to copy built images to tftp dir: /tftpboot [INFO] Successfully built u-boot-xlnx-scr cp -f /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/Pynq-Z1/petalinux_project/images/linux/boot.scr /home/xilinx/petalinux_projects/PYNQ/sdbuild/output/boot/Pynq-Z1/boot.scr mkdir -p /home/xilinx/petalinux_projects/PYNQ/sdbuild/ccache sudo rm -rf /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm mkdir /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm QEMU_EXE=/opt/qemu/bin/qemu-arm-static PYNQ_BOARD=Unknown ARCH=arm PYNQ_SDIST=/home/xilinx/petalinux_projects/PYNQ/sdbuild/prebuilt/pynq_sdist.tar.gz PYNQ_ROOTFS=/home/xilinx/petalinux_projects/PYNQ/sdbuild/prebuilt/pynq_rootfs.arm.tar.gz /home/xilinx/petalinux_projects/PYNQ/sdbuild/scripts/create_rootfs.sh /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm /home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm + set -e + target=/home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm + SRCDIR=/home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm + ARCH= + fss='proc dev sys' + echo /opt/qemu/bin/qemu-arm-static /opt/qemu/bin/qemu-arm-static + multistrap_conf=/home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm/multistrap.config + multistrap_opt= + '[' -n '' ']' + sudo -E multistrap -f /home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm/multistrap.config -d /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm multistrap 2.2.11 using /home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm/multistrap.config multistrap 2.2.11 using /home/xilinx/petalinux_projects/PYNQ/sdbuild/ubuntu/jammy/arm/multistrap.config Using foreign architecture: armhf multistrap building armhf multistrap on 'amd64' I: Setting /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm/lib64 -> /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm/lib symbolic link. I: Downloading ubuntu-keyring E: Can't find a source to download version '2021.03.26' of 'ubuntu-keyring:amd64' multistrap: Unable to download keyring package: '/home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm/' make: *** [Makefile:431: /home/xilinx/petalinux_projects/PYNQ/sdbuild/build/jammy.arm.stage1.tar.gz] Error 1 ``` **Any ideas on how to fix this `multistrap`/`ubuntu-keyring` issue for Jammy in this PYNQ v3.1 Docker flow?** Thanks! ---
**Author:** ![joshgoldsmith](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/joshgoldsmith/32/5347_2.png) [@joshgoldsmith](https://discuss.pynq.io/u/joshgoldsmith)\ **Post date:** [August 15, 2025, 2:08pm UTC](https://discuss.pynq.io/t/pynq-image-v3-1-for-pynq-z1-build-fails-during-rootfs-multistrap-ubuntu-keyring-error/8691/2 "2025-08-15T14:08:03Z")
Hi @Charlie_FPGA I was not able to replicate this issue. Following the steps in the documentation, I was able to build the Pynq-Z1 image. Can I just confirm you are downloading the most recent rootfs and sdist from [pynq.io](http://pynq.io)? - Arm32 rootfs: [https://download.amd.com/opendownload/pynq/jammy.arm.3.1.0.tar.gz](https://download.amd.com/opendownload/pynq/jammy.arm.3.1.0.tar.gz) - SDIST: [https://download.amd.com/opendownload/pynq/pynq-3.1.tar.gz](https://download.amd.com/opendownload/pynq/pynq-3.1.tar.gz) Also, when placing them inside `PYNQ/sdbuild/prebuilt/` you need to rename these files to `pynq_rootfs.arm.tar.gz` and `pynq_sdist.tar.gz`, respectively. I realise that is not in the documentation, so I will update that soon. Let me know how you get on. ---
**Author:** ![Charlie\_FPGA](https://avatars.discourse-cdn.com/v4/letter/c/5daacb/32.png) [@Charlie\_FPGA](https://discuss.pynq.io/u/Charlie_FPGA)\ **Post date:** [August 16, 2025, 2:55pm UTC](https://discuss.pynq.io/t/pynq-image-v3-1-for-pynq-z1-build-fails-during-rootfs-multistrap-ubuntu-keyring-error/8691/3 "2025-08-16T14:55:08Z")
Hello @joshgoldsmith, Thank you for your message. Yes, I also renamed the “agnostic-boards” rootfs and sdist. I was desperate and switched from the Docker workflow to running Pynq directly on the host (without Docker)… but I got exactly the same results! The issue was related to file permissions. My mistake was installing Petalinux as root using `sudo`. Petalinux 2024.1 installation steps: > **[AMD Technical Information Portal](https://docs.amd.com/r/2024.1-English/ug1144-petalinux-tools-reference-guide/Installation-Requirements)** Petalinux Installation command: > chmod 755 ./petalinux-v-final-installer.run > ./petalinux-v-final-installer.run After that everything is working smoothly. And the weird multistrap error disappeared. Thanks again for your support. BR, Carlos. ---
**Author:** ![system](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/system/32/2_2.png) [@system](https://discuss.pynq.io/u/system)\ **Post date:** [August 19, 2025, 2:55pm UTC](https://discuss.pynq.io/t/pynq-image-v3-1-for-pynq-z1-build-fails-during-rootfs-multistrap-ubuntu-keyring-error/8691/4 "2025-08-19T14:55:15Z")
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