TS-4800 Backup/Restore

From Technologic Systems Manuals

If you are using a Windows workstation there is no support for writing directly to block devices. However, as long as one of your booting methods still can boot a kernel and the initrd you can rewrite everything by using a usb drive. This is also a good way to blast many stock boards when moving your product into production. You can find more information about this method with an example script here.

Note: Note that the MBR installed by default on this board contains a 446 byte bootloader program that loads the initial power-on kernel and initrd from the first and second partitions. Replacing it with an MBR found on a PC would not work as a PC MBR contains an x86 code bootup program.

1 MicroSD Card

For imaging the SD card we recommend using a Linux or similar operating system that allows you to access a block device using dd. We do not support rewriting the SD card from Windows.

If you are reprogramming the SD card from your workstation you will also need to determine the SD card device. Once you have connected the SD card to your workstation you can usually find the correct block device in the output of "dmesg". For example:

 [  309.498834] sd 8:0:0:0: [sdb] 3862528 512-byte logical blocks: (1.97 GB/1.84 GiB)
 [  309.519814] sd 8:0:0:0: [sdb] Write Protect is off
 [  309.519818] sd 8:0:0:0: [sdb] Mode Sense: 03 00 00 00
 [  309.519819] sd 8:0:0:0: [sdb] Assuming drive cache: write through
 [  309.536025] sd 8:0:0:0: [sdb] Assuming drive cache: write through
 [  309.536029]  sdb: sdb1 sdb2 sdb3
 [  309.559672] sd 8:0:0:0: [sdb] Assuming drive cache: write through
 [  309.559676] sd 8:0:0:0: [sdb] Attached SCSI removable disk

On this system my SD card block device is /dev/sdb, but your system will likely be different. The block devices are allocated in order by the letter so the next USB drive connected would be /dev/sdc. 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.

WARNING: Many distributions will name your hard drive something like /dev/sda or /dev/hda which will have the same naming scheme as an SD card or a USB drive. Make sure you are aware which device is which before writing the disk.

The TS-4800 Debian distribution is available as a 2 GB disk image.

MicroSD.png Click to download the latest 2GB SD card image.

Once downloaded you can decompress the image using gunzip:

gunzip 2gbsd-latest.dd.gz

The resulting file will be "2gbsd-latest.dd".

If you are working with the SD card from your workstation, keep in mind that most Linux distributions will mount the partitions that they can as soon as the drive is inserted. This is desirable if you want to open the filesystem, but for dealing directly with the block device for performing backups or restoring an image this is dangerous to your data.

To verify if your workstation has mounted the block device on insertion:

mount
# look for your SD card block device to see if this is already mounted.
# use umount on each path listed as mounted to 
umount /media/sd-part1

Restore from Workstation

To write the latest image or restore to stock you would use the dd command. This will perform a byte for byte copy from our image. This contains the MBR boot code with the partition tables, the kernel, initrd, and Debian filesystem. No other formatting or partitioning is needed.

Write an image to the entire SD card:

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

If you want to write a new kernel, but not an entire image you can rewrite the second partition:

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

Backup from Workstation

To backup an entire SD card image:

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

This will create a dd file the size of the card.

Note: A MicroSD card from one manufacturer will likely not be the exact same size as another manufacturer's MicroSD card of the same size. Our partition layouts by default leave the last 10% of the images unallocated to account for the size difference of various manufacturers MicroSD cards. As long as you use our partition layout you should not need to be concerned with this, but if you create your own layout we strongly recommend leaving 10% of the disk unallocated.

If you would like to backup just the Kernel partition, you would grab partition 2.

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

Restore From the TS-4800

To write the latest image or restore to stock you would use the dd command. This will perform a byte for byte copy from our image. This contains the MBR boot code with the partition tables, the kernel, initrd, and Debian filesystem. No other formatting or partitioning is needed.

Write an image to the entire SD card:

dd if=/path/to/2GB-mSD-4800-latest.dd of=/dev/mmcblk0 conv=fsync

Kernel

dd if=/mnt/root/zImage of=/dev/mmcblk0p2 conv=fsync

Backup From the TS-4800

To backup an entire SD card image:

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

This will create a dd file the size of the card.

Note: A MicroSD card from one manufacturer will likely not be the exact same size as another manufacturer's MicroSD card of the same size. Our partition layouts by default leave the last 10% of the images unallocated to account for the size difference of various manufacturers MicroSD cards. As long as you use our partition layout you should not need to be concerned with this, but if you create your own layout we strongly recommend leaving 10% of the disk unallocated.

If you would like to backup just the kernel partition, you would grab partition 2.

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

2 XNAND

The XNAND is restorable from the stock SD card. Boot the the initrd (not Debian) and you can run one command to restore the stock mini-lenny distribution:

# createxnandroot
Preparing XNAND flash drive...
Copying Kernel and ramdisk from SD to XNAND...
done
Creating root filesystem...
done

This is normally the only necessary procedure, however under catastrophic circumstances (such as accidental dd onto the XNAND device), it may be necessary to run createxnandboot first.