EP9302 Restore CF
From embeddedTS Manuals
If backing up on a separate workstation, keep in mind windows does not have direct block device support needed to write these images. You will also need to determine the CF card device. You can usually find this in the output of 'dmesg' after inserting the CF card and you will typically see something like '/dev/sdb' as the block device and '/dev/sdb1' for the first partition. On some newer kernels you will see '/dev/mmcblk0' as the block device and '/dev/mmcblkop1' for the first partition. For these examples I will use the '/dev/mmcblk0' format.
If you are backing up directly on the board you will likely need to use some kind of offboard storage like a thumbdrive or external hard drive.
Backup
Entire CF card
dd if=/dev/mmcblk0 of=/path/to/backup.dd bs=32k
Restore
Entire CF card
dd if=/path/to/backup.dd of=/dev/mmcblk0 bs=32k