SD card cloning using the dd command

Insert the original SD card and check the name of the device (usually mmcblkX or sdcX):

sudo fdisk -l

You might see:

Device         Boot   Start      End  Sectors  Size Id Type
/dev/mmcblk0p1 *       2048  2099199  2097152    1G  c W95 FAT32 (LBA)
/dev/mmcblk0p2      2099200 31116287 29017088 13.9G 83 Linux

In my case the SD card is /dev/mmcblk0 (the *p1 and *p2 are the partitions).

Now you have to unmount the device:

sudo umount /dev/mmcblk0

Now to create an image of the device:

sudo dd if=/dev/mmcblk0 of=~/sd-card-copy.img

This will take a while.

Once it's finished, insert the empty SD card. If the device is different (USB or other type of SD card reader) verify its name and be sure to unmount it:

sudo fdisk -l
sudo umount /dev/mmcblk0

Write the image to the device:

sudo dd if=~/sd-card-copy.img of=/dev/mmcblk0

The write operation is much slower than before.

You should not be using dd on mounted devices. unmount all the partitions first, then your command should work.

I am using dd tool to clone usb sticks with multiple partitions, here is my command:

sudo dd if=/dev/sdb of=/dev/sdc bs=4096 conv=notrunc,noerror

notrunc - do not truncate the output file
noerror - continue after read errors