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Version: 029-rc4

Flashing via NXP uuu (Universal Update Utility)

Some i.MX-based boards support flashing via uuu (Universal Update Utility), NXP's USB-based download tool. This is useful for flashing eMMC without removing it from the board.

For board-specific hardware setup (boot switches, jumpers) see:

These machines build pv-flash-bundle (recipes-bsp/pv-flash/pv-flash-bundle.bb) as part of their release KAS target list. It packages a portable uuu binary, the production imx-boot, the compressed WIC image, and a generated uuu.auto / flash.sh into a single self-contained archive — no separate uuu install or manual command needed on the host. See pv-flash-bundle for how it's assembled.

build/tmp-scarthgap/deploy/images/<machine>/pv-flash-bundle-<machine>.tar.gz
tar xzf pv-flash-bundle-<machine>.tar.gz
cd pv-flash-bundle-<machine>
./flash.sh

flash.sh decompresses the bundled WIC image — .wic.zst via zstd if present (Variscite boards), otherwise .wic.gz via zcat — and invokes sudo ./uuu ./, which reads uuu.auto and runs the full SDP/SDPS → fastboot → eMMC flash sequence (the MEK's i.MX8QXP silicon uses SDPS "stream" mode instead of plain SDP; see pv-flash-bundle for the difference). Put the board into USB download mode first (see the board-specific page linked above) and connect USB before running it.

zcat (part of gzip) is virtually always present; zstd may need installing separately (sudo apt install zstd) if the bundle ships a .wic.zst.

These boards' own production bootloaders already self-enter SDP/fastboot download mode — unlike Toradex, no separate recovery U-Boot build is needed (see pv-flash-bundle: why Variscite and the MEK don't need a recovery multiconfig).

Manual flashing (without pv-flash-bundle)​

Useful if you already have uuu installed and just want to reflash a WIC image without extracting a bundle, or for boards/builds that don't produce one.

Prerequisites​

  • USB Type-A to USB-C (or Micro-USB) cable connected to the board's USB OTG / download port
  • uuu installed on the host
# Install uuu on Debian/Ubuntu
sudo apt install uuu

# Or download the binary from GitHub releases

Locating the artifacts​

After a successful build, the WIC image and SPL/u-boot binaries are at:

build/tmp-scarthgap/deploy/images/<machine>/
  pantavisor-starter-<machine>*.wic
  imx-boot                      # SPL + u-boot FIT image (symlink)

1. Put the board into USB download (serial download) mode​

See the board-specific page for the exact switch/jumper settings.

2. Connect USB and verify​

# uuu should detect the board
sudo uuu -lsusb

You should see an SE Blank or SDP:MX8M* device listed.

3. Flash with uuu​

Option A — using the WIC image directly​

sudo uuu -b emmc_all imx-boot-<machine>*.bin pantavisor-starter-<machine>*.wic

Option B — using a board-vendor uuu script (Variscite)​

Variscite BSPs ship a uuu_imx_android_flash.sh script. Refer to the Variscite wiki for the board-specific command.

4. Boot normally​

Remove the download-mode jumper/switch, then power-cycle the board. It will boot from eMMC.

Notes​

  • uuu requires root or udev rules granting access to the USB device. Add the NXP vendor udev rule if you get permission errors: 
    echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="1fc9", MODE="0666"' \
        | sudo tee /etc/udev/rules.d/70-nxp-uuu.rules
    sudo udevadm control --reload-rules
  • The emmc_all profile (and the bundled uuu.auto) write the full WIC image (boot partitions + rootfs). Use emmc if you only want to update the rootfs partition manually.
  • Variscite's production bootloader already self-enters SDP/fastboot download mode, so no separate recovery build is needed — unlike the Toradex boards, which use pv-flash-bundle with a recovery U-Boot.