0. !!! WARNING !!! ‘dd’ may damage your system …

Please use disks with no data or non critical data, and use dd with extreme caution. Test things first, Disks, Flash Drivers and operating systems differ so be carefull.

1. Before clonning let’s check the state our original disk sdc, see the rw flag bellow RO.

# blockdev -v --getro /dev/sdc
get read-only: 0

# blockdev -v --getro /dev/sdc1
get read-only: 0

# blockdev --report  /dev/sdc
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw   256   512  4096          0   1000204886016   /dev/sdc

# blockdev --report  /dev/sdc1
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw   256   512  4096       2048   1000203091968   /dev/sdc1

# hdparm -r1 /dev/sdc

2. Lock property of device sdc, this will set the device and partition to read-only mode

blockdev --setro /dev/sdc
blockdev --setro /dev/sdc1
# blockdev -v --getro /dev/sdc
get read-only: 1

# blockdev -v --getro /dev/sdc1
get read-only: 1
We also can use the hdparm instead of blockdev
hdparm -r1 /dev/sdc

 setting readonly to 1 (on)
 readonly      =  1 (on)

# hdparm -r /dev/sde

 readonly      =  1 (on)

3. Insert the clean device

dmesg -T 

[Tue Jul  5 13:13:41 2016]  sdg: sdg1
[Tue Jul  5 13:13:41 2016] sd 5:0:0:0: [sdg] Attached SCSI disk

4. Clone the devices with dd

Used device ids instead of sda, sdX, etc it’s safer. :-)

ls -lh /dev/disk/by-id/* | grep -i kingston | awk '{ print $9}'
/dev/disk/by-id/usb-Kingston_DT_HyperX_000000-0:0 -> ../../sde

option 1 ( safer )

sudo dd status=progress if=/dev/disk/by-id/usb-Kingston_DT_HyperX_0011100-0:0 /dev/disk/by-id/ata-Hitachi_HDT000_XXX

option 2 ( risky )

sudo dd status=progress if=/dev/sdc /dev/sdg

In my Arch Linux i have progress with dd version 8.25,

# dd --version
dd (coreutils) 8.25

On some of Debian/Ubuntu or other Linux Distro the option is to use dd_rescue, that has progress and other nice features for data recovery.

dd_rescue /dev/sdc /dev/sdg

After using deftlinux for some data recovery, i found that is possible to set devices in read only mode. You can check details in the here deft-quickguide.