This topic explains how to boot Digi Embedded Yocto images without updating the firmware on the internal eMMC. This is helpful during the development phase, as it preserves the original firmware on the SOM.

Open a serial connection

You must open a serial connection to communicate with your device.

  1. Open a serial connection using any terminal program such as Tera Term, Minicom, Coolterm, or HyperTerminal. This documentation demonstrates using Minicom to work with the device command line.

    Use the following settings:

    Parameter Value

    Port

    Serial port where the device is connected

    Baud rate

    115200

    Data bits

    8

    Parity

    None

    Stop bits

    1

    Flow control

    None

  2. Reset the device by pressing the reset button on the board. Then immediately press any key in the serial terminal to stop the auto-boot process. The U-Boot bootloader prompt displays:

    U-Boot SPL dub-2024.04-r5.2+g25c8faec2f83+p0 (May 27 2026 - 10:40:43 +0000)
    SOC: 0xb0009500
    LC: 0x40010
    SYS Boot reason: por, origin: -1, errid: -1
    SYS shutdown reason: por, origin: -1, errid: -1
    DDRMIX is powered UP
    Normal Boot
    Trying to boot from MMC1
    Primary set selected
    Load image from MMC/SD 0xc9400
    NOTICE:  BL31: v2.10.0  (release):lf-6.6.52-2.2.2-dirty
    NOTICE:  BL31: Built : 09:57:54, Oct 17 2025
    
    
    U-Boot dub-2024.04-r5.2+g25c8faec2f83+p0 (May 27 2026 - 10:40:43 +0000)
    
    CPU:   i.MX95 rev2.0 at 1800MHz
    CPU:   Extended Industrial temperature grade (-40C to 125C) at 28C
    LM Boot reason: por, origin: -1, errid: -1
    LM shutdown reason: por, origin: -1, errid: -1
    DRAM:  1.8 GiB
    Error: ele_read_common_fuse: ret -5, fuse_id 0x139, response 0xbc29
    ahab read fuse failed -5, 0xbc29
    Cannot read HWID
    MCA:   HW_VER=1  FW_VER=0.09
    cfg name not match mx95alt:ccimx95dvk, ignore
    Core:  303 devices, 36 uclasses, devicetree: separate
    MMC:   FSL_SDHC: 0, FSL_SDHC: 1
    Loading Environment from MMC... OK
    [*]-Video Link 0clk disp1pix already disabled
    (1280 x 800)
            [0] display-controller@4b400000, video
            [1] channel@0, video_bridge
            [2] bridge@8, video_bridge
            [3] channel@0, display
            [4] lvds0_panel, panel
    In:    serial
    Out:   serial
    Err:   serial
    Model: Digi International ConnectCore 95 DVK
    ConnectCore 95 SOM variant 0x03: 1.8 GiB LPDDR5, Wi-Fi, Bluetooth
    ConnectCore 95 SMARC variant 0x03: Dual Ethernet, MCA
      Board version 2, ID undefined
    Boot:  MMC0
    
    BuildInfo:
      - SM firmware Build 733, Commit ecd89d0b, May 05 2026 00:00:18
      - ELE firmware version 2.0.3-5f1204b7
    
    Error: ele_read_common_fuse: ret -5, fuse_id 0x139, response 0xbc29
    ahab read fuse failed -5, 0xbc29
    flash target is MMC:0
    Net:   eth0: enetc-0 [PRIME], eth1: enetc-1
    Fastboot: Normal
    Normal Boot
    Hit any key to stop autoboot:  0
    
    => 

Boot the system from network

This shows how to transfer the images to the target via TFTP or NFS, and mount an NFS root file system.

This requires that you set up your PC workstation as explained in Set up native Linux PC.

1. Prepare the device artifacts

  1. Get the Digi Embedded Yocto firmware images to boot from network:

    • The kernel file: Image.gz-ccimx95-dvk.bin.

    • The device tree: ccimx95-dvk.dtb.

    • Any device tree overlays files that apply to your hardware: <device-tree-overlay-file>.dtbo (see Pre-compiled device tree overlays).

    • The compressed root file system: <rootfs-file>.tar.xz.

    1. After building the Digi Embedded Yocto firmware, you can find the image files inside the project directory at <project_folder>/tmp/deploy/images/ccimx95-dvk.

    2. You can download Digi-provided pre-built images from XWayland images.

  2. Untar the root file system tarball (*.tar.xz) in the NFS exported directory of your development workstation. See Set up native Linux PC.

    $ sudo tar xvfp <image>.tar.xz -C /exports/nfsroot-ccimx95_dvk
  3. Copy the kernel Image.gz-ccimx95-dvk.bin file to the TFTP exported directory of your development workstation.

    $ sudo cp Image.gz-ccimx95-dvk.bin /tftpboot
  4. Copy the device tree file to the TFTP exported directory of your development workstation.

    $ sudo cp ccimx95-dvk.dtb /tftpboot
  5. (Optional) Copy any device tree overlay *.dtbo files that apply to your variant to the TFTP exported directory of your development workstation.

    $ sudo cp <device-tree-overlay-file>.dtbo /tftpboot

2. Configure your device’s network settings

  1. Get a dynamic IP for your target:

    => setenv autoload no
    => dhcp

    or you can set a static IP:

    => setenv ipaddr 192.168.115.222
  2. Configure the IP of the development workstation with TFTP and NFS servers installed. See Set up native Linux PC:

    => setenv serverip 192.168.115.1

3. Boot from network

Boot from TFTP+NFS

  1. Set the directory with the rootfs to mount. This directory is the one exported via NFS in your development workstation. See Set up an NFS server.

    => setenv rootpath /exports/nfsroot-ccimx95_dvk
  2. Specify the device tree (*.dtb) file name. This is the name of the *.dtb file you copied to the TFTP exported directory of your development workstation.

    => setenv fdt_file ccimx95-dvk.dtb
  3. (Optional) Use a comma-separated list to specify the device tree overlay (*.dtbo) files you want to apply. These are the names of the *.dtbo files you copied to the TFTP exported directory of your development workstation.

    => setenv overlays <overlay1>.dtbo,<overlay2>.dtbo
  4. Establish the kernel file name. This is the name of the file you copied to the TFTP exported directory of your development workstation.

    => setenv imagegz Image.gz-ccimx95-dvk.bin
  5. Save the changes.

    => saveenv
  6. Boot from TFTP.

    => dboot linux tftp

    You can make these changes persistent by writing the following command:

    => setenv bootcmd 'dboot linux tftp'
    => saveenv

The target now loads the kernel and device tree from the TFTP server and the root file system from the NFS server.

Boot entirely from NFS

To avoid using TFTP for kernel and device tree files and boot everything from NFS, copy the kernel Image.gz-ccimx95-dvk.bin, device tree ccimx95-dvk.dtb and device tree overlay files to the NFS-exported directory of your development workstation (instead of to the TFTP directory). See Set up an NFS server.

=> dboot linux nfs

Boot from microSD card

U-Boot can start a complete Digi Embedded Yocto system from a microSD card. See Boot from microSD card for instructions on creating a bootable microSD card and booting from it.