CL-SOM-iMX7: Linux: Manual Installation: Source: SD

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This article provides an introduction on how to install the Linux kernel and the example root filesystem image on the CompuLab CL-SOM-iMX7 System-on-Module / Computer-on-Module eMMC internal storage device using SD card as the installation source.

Preparation steps

  • Obtain a PC workstation with a serial communication port.
  • For networked installation you need to install a TFTP server on the host PC. For Windows machines we recommend TFTPD32 included in the Linux package for CL-SOM-iMX7 (link below).
  • Download the CL-SOM-iMX7 BSP binary from CompuLab website. Unzip the package to a directory on your host workstation.
  • All image files mentioned below can be found in the install sub-directory.
  • Connect the host PC to the SBC-iMX7 USB console connector (P7) with the USB cable supplied in the evaluation kit.

Preparing installation media

  • Obtain an SD card. Any commercially available micro SD card of 1GB (or larger) may be used.
  • Create a first partition on it. The partition can be formatted either ext2/3/4 or FAT file system.
  • Copy kernel.img, ramdisk.img, rootfs.tar.bz2, imx7d-*.dtb and zImage from the unzipped Linux package to the root directory on the first partition of the SD card.

Boot into the installation environment (ramdisk)

  • Start terminal emulation software on your PC with the following serial port settings:
Baud Rate Data Bits Stop Bits Parity Flow Control
115200 8 1 none none
  • Plug the installation media (SD card) into the SD socket (P9) on the SBC-iMX7.
  • Make sure no other removable media (e.g. USB storage) is plugged.
  • Turn on the device. Press a key to prevent a possible autoboot and get into the U-Boot command prompt.
Admolition note.png If the boot settings of your device are different than the default, you may need to press and hold Ctrl-C while turning the device on, in order to get command prompt.
  • Use the following U-Boot commands to boot the installation environment on the device:
setenv fdtfile imx7d-sbc-imx7.dtb
setenv ramdisk_addr 0x82000000; setenv fdtaddr 0x83000000
setenv bootargs 'root=/dev/ram0 rw ramdisk_size=16384 console=ttymxc0,115200 vram=16M'
mmc rescan
load mmc 0 ${loadaddr} kernel.img && load mmc 0 ${fdtaddr} ${fdtfile} && load mmc 0 ${ramdisk_addr} ramdisk.img
bootz ${loadaddr} ${ramdisk_addr} ${fdtaddr}

Install Linux Images

The next step is installing the kernel and Debian Linux images.

Mount the SD Card

  • The source SD card is mounted automatically under /mnt/install/.
  • If for some reason the micro SD card hasn't been mounted automatically, use the following mount command:
root@cl-ramdisk:~# mount /dev/mmcblk0p1 /mnt/install

Install Images on eMMC

  • Unmount all eMMC partitions:
root@cl-ramdisk:~# umount -l /dev/mmcblk2p*
  • Clean up the on the eMMC flash:
root@cl-ramdisk:~# dd if=/dev/zero of=/dev/mmcblk2 bs=1M count=1
root@cl-ramdisk:~# hdparm -z /dev/mmcblk2
  • Create two partitions for the Linux kernel (EXT2 100M) and root file system (EXT4 the rest of the disk) on the eMMC flash:
root@cl-ramdisk:~# echo -e "n\np\n1\n\n+100M\nn\np\n2\n\n\nw\neof\n" | fdisk /dev/mmcblk2
  • Format the first partition with EXT2 file system:
root@cl-ramdisk:~# mkfs.ext2 -L boot /dev/mmcblk2p1
  • Format the second partition with EXT4 file system:
root@cl-ramdisk:~# mkfs.ext4 -L rootfs /dev/mmcblk2p2
  • Mount both partitions:
root@cl-ramdisk:~# mkdir -p /media/boot && mount /dev/mmcblk2p1 /media/boot
root@cl-ramdisk:~# mkdir -p /media/rootfs && mount /dev/mmcblk2p2 /media/rootfs
  • Copy zImage and imx7d-*imx7.dtb to the first (EXT2) partition:
root@cl-ramdisk:~# cp /mnt/install/zImage /mnt/install/imx7d-*.dtb /media/boot && sync
  • Extract the content of rootfs.tar.bz2 onto the second partition:
root@cl-ramdisk:~# tar --numeric-owner -xpf /mnt/install/rootfs.tar.bz2 -C /media/rootfs && sync
  • Unmount both partitions:
root@cl-ramdisk:~# umount /dev/mmcblk2p1
root@cl-ramdisk:~# umount /dev/mmcblk2p2

After Installation

  • Remove the micro SD card and reboot the device
  • Press a key to prevent a possible autoboot and get into the U-Boot command prompt.
  • Use the following U-Boot commands to configure eMMC as the main storage for both Linux kernel and root filesystem images:
env default -a
setenv bootdelay 3
setenv kernel zImage
setenv loadaddr 0x80800000
setenv fdtfile imx7d-sbc-imx7.dtb
setenv fdtaddr 0x83000000
setenv mmcroot "/dev/mmcblk2p2 rootwait rw"
setenv loadimage 'load mmc 1:1 ${loadaddr} ${kernel}'
setenv loadfdt 'load mmc 1:1 ${fdtaddr} ${fdtfile}'
setenv bootargs "console=ttymxc0,115200 root=${mmcroot}"
setenv bootcmd 'run loadimage; run loadfdt; bootz ${loadaddr} - ${fdtaddr}'
  • To save this configuration:
  • To boot Linux type:
run bootcmd

See also