TS-4900 eMMC Backup/restore

From Technologic Systems Manuals

Write the image:

These commands assume the unit is booted from SD and eMMC is set up with a single partition:

# Verify nothing else has this mounted
umount /dev/mmcblk2p1

mkfs.ext3 /dev/mmcblk2p1
mkdir /mnt/emmc
mount /dev/mmcblk2p1 /mnt/emmc
wget ftp://ftp.embeddedarm.com/ts-socket-macrocontrollers/ts-4900-linux/distributions/yocto/morty/ts-x11-image-tsimx6-latest.rootfs.tar.bz2
tar --numeric-owner -xf ts-x11-image-tsimx6-latest.rootfs.tar.bz2 -C /mnt/emmc
umount /mnt/emmc
sync
Note: The ext4 filesystem can be used instead of ext3, but it may require additional options. U-Boot does not support the 64bit addressing added as the default behavior in recent revisions of mkfs.ext4. If using e2fsprogs 1.43 or newer, the options "-O ^64bit,^metadata_csum" must be used with ext4 for proper compatibility. Older versions of e2fsprogs do not need these options passed nor are they needed for ext3.

After the tarball is unpacked, the data on disk can be verified with md5sum:

# Drop any block cache
echo 3 > /proc/sys/vm/drop_caches
mount /dev/mmcblk2p1 /mnt/emmc
cd /mnt/emmc/
sudo md5sum -c md5sums.txt
umount /mnt/emmc
sync

The md5sum command will report what differences there are, if any, and return if it passed or failed.

Backup the image:

First boot the device to any compatible bootable SD card. The SD needs have enough free space for the compressed image of the data on the eMMC. Our default image eMMC image is ~500MB when compressed. A tarball of the eMMC can be created on the SD card with the following commands:

mkdir /mnt/emmc/
mount /dev/mmcblk2p1 /mnt/emmc/
cd /mnt/emmc/
tar --numeric-owner -cjf /root/emmc-backup.tar.bz2 *
cd /
umount /mnt/emmc/