VAR-SOM-MX7 Debian Recovery SD card

From Variscite Wiki
VAR-SOM-MX7 - Debian recovery SD card

Variscite provides a recovery SD card image that can be used to install the pre-built Debian images into the internal storage device of the SOM.

1 Download the recovery SD card image

Download mx7-som-debian-recovery-sd.vXX.img.gz (latest) from Variscite's FTP server:

2 Write the image to an SD card

2.1 Using a Linux based host

Plug-in the SD card to your Linux HOST PC, run dmesg and see which device is added (i.e. /dev/sdX or /dev/mmcblkX)

$ gunzip mx7-som-debian-recovery-sd.vXX.img.gz
$ sudo umount /dev/sdX*
$ sudo dd if=mx7-som-debian-recovery-sd.vXX.img of=/dev/sdX bs=1M; sync

(Replace /dev/sdX with your actual device)

2.2 Using a Windows based host

Download Win32 Disk Imager from:, install and run it.
Select the image file, and the SD card device - double check that the device is correct to avoid accidentally overwriting a different device.
Click on "Write".
No need to format the SD card before writing the image to it.

3 Recover NAND flash/eMMC

  • Power-off the board.
  • Insert the SD card into the SD card slot of the carrier board (DVK)
  • Make sure the Boot DIP switches are set to SD card: Setting the Boot DIP switches
  • Power up the board - it will boot into Linux from the SD card

3.1 Flash from command line

  • Login as root (no password)
  • From Linux command line, type the following
# -r nand (Follow instructions)
# -r nand -m	- Flash Debian images with Cortex-M4 support into NAND flash (for SOMs with NAND flash)

In case you are using a SOM with eMMC, run the following command as root to install Debian on it:

# -r emmc (Follow instructions)

3.2 SD card image file tree

└── Debian
    ├── imx7d-var-som-emmc.dtb
    ├── imx7d-var-som-emmc-m4.dtb
    ├── imx7d-var-som-nand.dtb
    ├── imx7d-var-som-nand-m4.dtb
    ├── rootfs.tar.gz
    ├── rootfs.ubi.img
    ├── SPL.mmc
    ├── SPL.nand
    ├── u-boot.img.mmc
    ├── u-boot.img.nand
    └── zImage
The and script files are located at /usr/sbin/