75XX MicroSD Recovery

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 SD card device. You can usually find this in the output of 'dmesg' after inserting the SD 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. Make sure you have any nbd devices unmounted before trying to restore new ones.

You can find the latest SD card image here.

From Workstation

Backup entire SD card

dd if=/dev/mmcblk0 of=/path/to/backup.dd bs=32k

Restore the entire SD card

dd if=/path/to/backup.dd of=/dev/mmcblk0 bs=32k

Backup Kernel

dd if=/dev/mmcblk0p2 of=/path/to/zImage bs=32k

Restore Kernel

dd if=/path/to/zImage bs=32k of=/dev/mmcblk0p2