SD Card

Create a Bootable SD Card

In order to create a bootable SD card a BSP image has to be flashed onto it. Flashing is a term used to describe the process of burning software images to a flash memory storage device, hence flashing. This section of the guide will outline the steps for flashing the complete .wic.xz image format to an SD Card. The .wic.xz image format is a compressed binary consisting of all the necessary binaries, as well information about the require disk partitions needed for booting the phyCORE-AM64x into Linux. This includes the bootloader, kernel and root filesystem.

In order to boot the phyCORE-AM64x development kit into Linux, it must load valid software from a memory storage device. It is typical for production systems to boot software from an onboard (non-removable) memory storage device such as eMMC memory but booting from an SD Card is more convenient during development. The phyCORE-AM64x development kit is configured to boot from an SD Card by default.

A pre-configured SD card is included with your development kit but this guide will walk through the creation of a bootable SD Card using Pre-Built Binaries or images you have generated on your own by following the Build the BSP guide.

Windows

What you’ll need

  • SD Card Reader

  • 4GB micro-SD Card or larger (Included in development kit)

Step-by-Step

  • Download the SD card flasher app BalenaEtcher

  • Download the prebuilt SD card image BSP-Yocto-AM64x-PD23.1.0.

  • Now that your system is setup, use the BalenaEtcher SD card flasher to create a bootable SD card.

    1. Open BalenaEthcher and select “Flash from file”.

    2. Select the ‘phytec-headless-image-phyboard-electra-am64xx-1.wic.xz’ SD card image file from your Downloads folder.

    3. Then insert the micro-SD card into the SD card reader.

    4. Click on “Select Target” and select the SD card.

    5. Begin flashing the SD card by pressing “Flash!”

    6. Once BalenaEtcher is done flashing the SD card image, eject the SD card from the Host PC and insert the SD card into the development kit.

See the section “Booting from SD Card” for more information.

Linux Machine

What you’ll need

  • Ubuntu 18.04 LTS, 64-bit Host Machine

    • If using a virtual machine, VMWare Workstation, VMWare Player, and VirtualBox are all viable solutions.

  • SD Card Reader

  • 4GB micro-SD Card or larger (Included in development kit)

Step-by-Step

  • Getting your Ubuntu host machine up-to-date.

    Host (Ubuntu)
    sudo apt-get update
    
  • Run the following command without the SD card connected to the host machine.

    Host (Ubuntu)
    ls /dev/sd*
    
  • Connect the SD card to the Ubuntu host machine.

  • Run the following command again with the SD card connected to the host machine.

    Host (Ubuntu)
    ls /dev/sd*
    
  • Unmount the SD card from the host machine. Do not remove the card from the machine.

    Host (Ubuntu)
    umount /dev/sdX*
    
  • Navigate to the directory containing the ‘.wic.xz’ file you wish to flash. This might be wherever you downloaded the pre-built image or it could be the deployment directory of your local BSP build at $BUILDDIR/deploy/images/phyboard-electra-am64xx-1/

    Host (Ubuntu)
    cd <image location>
    
  • Flash the .wic.xz image to the SD Card:

    Host (Ubuntu)
    sudo xz -dc phytec-headless-image-phyboard-electra-am64xx-1.wic.xz | sudo dd of=/dev/sdX bs=8192 conv=fsync
    

    Note

    Note that you have to flash the SD Card image to the entirety of the SD Card. This is done by specify the output location of the flashing command without a numbered partition specified. For example, if you try to flash the SD Card image to /dev/sda1 this will result in a improperly formatted SD Card.

  • Unmount the SD card from your Linux machine.

    Host (Ubuntu)
    umount /media/<user>/boot /media/<user>/root
    
  • Insert the micro-SD card into the development kit. For more information on how to boot from SD card, see the section “Booting from SD Card”.

Updating Individual Parts of the SD Card (Advanced, Linux Machine)

Once the SD card has been formatted the first time via flashing the complete .wic.xz image, you do not need to flash the entire contents of the SD Card image again to update the image components. The bootloader, kernel and root filesystem can be updated individually (depending on the changes being tested) to potentially save a lot of time during development. Find all the images and binaries for the phyCORE-AM64x development kit here.

Updating the Kernel

  • First, remove the existing kernel image and device tree files:

    Host (Ubuntu)
    sudo rm /media/<user>/boot/Image
    sudo rm /media/<user>/root/boot/k3-am642-phyboard-electra-rdk.dtb
    
  • Copy the new Linux kernel, device tree binaries and applicable device tree overlays to the SD card’s Boot partition:

    Host (Ubuntu)
    sudo cp Image /media/<user>/root/boot/
    sudo cp k3-am642-phyboard-electra-rdk-phyboard-electra-am64xx-1.dtb /media/<user>/root/boot/
    sudo sync /media/<user>/root/
    

Updating the Root Filesystem

  • Connect your SD card to the Host Machine and identify the root filesystem’s mount point. This can be down using the mount utility from above:

    Host (Ubuntu)
    user@ubuntu:~$ mount
    sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
    proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
    udev on /dev type devtmpfs (rw,nosuid,relatime,size=1975752k,nr_inodes=493938,mode=755)
    devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
    tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=400172k,mode=755)
    /dev/sda1 on / type ext4 (rw,relatime,errors=remount-ro)
    ...
    /dev/sde1 on /media/<user>/boot type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)
    /dev/sde2 on /media/<user>/root type ext4 (rw,nosuid,nodev,relatime,uhelper=udisks2)
    

    We can see in this example output the SD card’s two partitions are mounted on /media/<user>/boot and /media/<user>/root respectively.

  • Delete the contents of the SD card’s root filesystem partition:

    Host (Ubuntu)
    sudo rm -rf /media/<user>/root/*
    
  • Unpack the root filesystem tarball into the SD card’s existing root filesystem partition’s mount point:

    Host (Ubuntu)
    sudo tar -xf phytec-headless-image-phyboard-electra-am64xx-1.tar.xz -C /media/<user>/root/
    sudo sync /media/<user>/root/
    

Updating the Bootloader

  • Delete the contents of the SD card’s boot partition:

    Host (Ubuntu)
    sudo rm /media/<user>/boot/*
    
  • Copy the bootloader binaries to the SD card:

    Host (Ubuntu)
    sudo cp tiboot3.bin /media/<user>/boot/
    sudo cp tispl.bin /media/<user>/boot/
    sudo cp u-boot.img /media/<user>/boot/
    sudo sync /media/<user>/boot/
    

Booting from SD Card

The phyCORE-AM64x development kit is configured to boot from an SD Card slot by default and basic steps for performing this and establishing serial communication are outlined in the Quickstart.Boot switch (aka DIP switches) settings determine the location and method the boot ROM loads the first stage bootloader into memory before executing it.

Boot Switch Settings

  • S10 should be ON to overide default boot settings.

SD Boot Switch phyBOARD-AM64 close-up boot switches