?Table of Contents

• How To Make A SD Image From SD Bootable OS
  • Abstract
  • Prerequisites
    • Steps:
    • (1) Unpacking you SD card OS.
    • 1.Unpacking the first partition (including script.bin uImag bootscr )
    • 2.Unpacking the second partion (file systerm)
    • (2) Begining making imgae
    • 1.Create a empty image and write uboot in it
    • 2.Partitioning
    • 3.Mounting the partition and move OS to image

How To Make A SD Image From SD Bootable OS

About this Article

• Author: sam — [e-mail] — 2014/03/13 01:33
• Copyrights: CC Attribution-Share Alike 3.0 Unported
• Contributors: Cubieboard Community : …

Abstract

we may want to backup our SD bootable OS which have installed many application software. We can make SD Bootable OS into a SD card image.here is guide for you.This guide is for Linux platform only.

Prerequisites

• Any Linux environment,? we want fdisk, dd, tar, commands
• An SD Card which must have installed a OS

Steps:

(1) Unpacking you SD card OS.

1.Unpacking the first partition (including script.bin uImag bootscr )

$sudo umount /media/*$sudo mount /dev/sdb1 /mnt    $sudo tar -cp * |sudo gzip -9 > ~/bootfs.tar.gz$sudo umount /mnt

2.Unpacking the second partion (file systerm)

 $sudo mount /dev/sdb2 /mnt $sudo tar -cp * |sudo gzip -9 > ~/rootfs.tar.gz

(2) Begining making imgae

1.Create a empty image and write uboot in it

$ mkdir WORK_DIR$cd $WORK_DIR  //creating empty image , this space is 2.5G,you can change by yourself$sudo dd if=/dev/zero of=disk.img count=5000000    //associating /dev/loop0 with the image$sudo losetup /dev/loop0 disk.img               $sudo dd if=/dev/zero of=/dev/loop0 bs=1k count=1024   $sudo dd if=u-boot-sunxi-with-spl.bin of=/dev/loop0 bs=1024 seek=8  //write uboot in image

2.Partitioning

$sudo fdisk /dev/loop0

Using the fdisk command to create 2 partitions on the SD Card, e.g.

• 1st partitions start from 2048 sectors, 64MB in size
• 2nd partitions just keep it all default

Show bellow

Device Boot            Start         End      Blocks   Id  System/dev/loop0p1            2048      133119       65536   83  Linux/dev/loop0p2          133120     4999999     2433440   83  Linu

Also we recommend you to look at Bootable_SD_card

3.Mounting the partition and move OS to image

$cd $WORK_DIRassociateing /dev/loop0 with image again $sudo losetup -d /dev/loop0 && sudo losetup /dev/loop0 disk.img //associateing  /dev/loop1 with the first partition of /dev/loop0,1048576=512*2048)  $sudo losetup -o 1048576 /dev/loop1 /dev/loop0            //format the first partition$sudo mkfs.vfat /dev/loop1  //format the second partitions$sudo mkfs.ext4 /dev/loop2   $sudo mount /dev/loop1 /mnt   //decompressing bootfs.tar.gz to the first partition$sudo tar -zxvf ~/bootfs.tar.gz -C /mnt  $sudo umount /mnt$sudo mount /dev/loop2 /mnt  //decompressing rootfs.tar.gz to second partition$sudo tar -zxvf ~/rootfs.tar.gz -C /mnt $sync && umount /mnt//cancel associating$losetup -d /dev/loop2  //cancel associating$losetup -d /dev/loop1   //cancel associating$losetup -d  /dev/loop0