75XX XNAND Recovery

From Technologic Systems Manuals

This needs to be done directly on the SBC. If you are running from the SD card the XNAND will not be mounted by default. You can also boot to the initrd of the XNAND and unmount the xnand:

umount /mnt/root

If there is no /mnt/root/ directory then the system is still booted to Debian and you should not proceed with the backup/restore sections. The image that is written or read back will be corrupt.

WARNING: Rewriting the XNAND from a Debian filesystem on the XNAND will result in a corrupted image.

You can find the latest xnand image here. Once downloaded you can decompress the image using bzip2:

bzip2 -d xnandimg-latest.dd.bz2

The resulting file will be "xnandimg-latest.dd".

Backup

To create the image first connect a USB drive and then power the device on. Boot to the busybox environment and not the full Debian. The USB drive should be formatted with ext2/3 or fat32.

killall nandctl
mkdir /mnt/usb
mount /dev/sda1 /mnt/usb
nandctl -XR 2048 -z 131072 > /mnt/usb/backup.dd
umount /mnt/usb
sync

To backup the entire image containing the MBR/Kernel/Initrd/Debian you can run one command:

nandctl -XR 2048 -z 131072 > /path/to/backup.dd

To backup the current kernel:

nandctl -XR 4096 -z 512 --seek part1 > /path/to/kernel

To backup the initrd:

nandctl -XR 4096 -z 512 --seek part2 > /path/to/initrd

Restore

To write the image first connect a USB drive with the image and then power the device on. Boot to the busybox environment and not the full Debian. The USB drive should be formatted with ext2/3 or fat32.

killall nandctl
mkdir /mnt/usb
mount /dev/sda1 /mnt/usb
nandctl -XW 2048 -z 131072 -i /mnt/usb/backup-image.dd
umount /mnt/usb
sync

To write the entire image containing the MBR/Kernel/Initrd/Debian you can run one command:

nandctl -XW 2048 -z 131072 -i /path/to/xnandimg-latest.dd

To write a new kernel:

dd if=zImage bs=512 conv=sync | nandctl -X -W 4095 -k kernel -z 512 -i -

To write a new initrd:

dd if=initrd bs=512 conv=sync | nandctl -X -W 4095 -k initrd -z 512 -i -