How to backup/change boot image? topic

Hi,

Do you know how to backup boot image?
I read that its in param partition but when I open it was nothing inside :(

I found the param by this:
ls -l /dev/block/platform/msm_sdcc.1/by-name

Code:

---

lrwxrwxrwx root    root              2014-01-11 04:52 aboot -> /dev/block/mmcbl
k0p6
lrwxrwxrwx root    root              2014-01-11 04:52 apnhlos -> /dev/block/mmc
blk0p1
lrwxrwxrwx root    root              2014-01-11 04:52 backup -> /dev/block/mmcb
lk0p17
lrwxrwxrwx root    root              2014-01-11 04:52 boot -> /dev/block/mmcblk
0p14
lrwxrwxrwx root    root              2014-01-11 04:52 cache -> /dev/block/mmcbl
k0p24
lrwxrwxrwx root    root              2014-01-11 04:52 dbi -> /dev/block/mmcblk0
p4
lrwxrwxrwx root    root              2014-01-11 04:52 ddr -> /dev/block/mmcblk0
p5
lrwxrwxrwx root    root              2014-01-11 04:52 efs -> /dev/block/mmcblk0
p11
lrwxrwxrwx root    root              2014-01-11 04:52 fota -> /dev/block/mmcblk
0p16
lrwxrwxrwx root    root              2014-01-11 04:52 fsc -> /dev/block/mmcblk0
p19
lrwxrwxrwx root    root              2014-01-11 04:52 fsg -> /dev/block/mmcblk0
p18
lrwxrwxrwx root    root              2014-01-11 04:52 hidden -> /dev/block/mmcb
lk0p25
lrwxrwxrwx root    root              2014-01-11 04:52 modem -> /dev/block/mmcbl
k0p2
lrwxrwxrwx root    root              2014-01-11 04:52 modemst1 -> /dev/block/mm
cblk0p12
lrwxrwxrwx root    root              2014-01-11 04:52 modemst2 -> /dev/block/mm
cblk0p13
lrwxrwxrwx root    root              2014-01-11 04:52 pad -> /dev/block/mmcblk0
p9
lrwxrwxrwx root    root              2014-01-11 04:52 param -> /dev/block/mmcbl
k0p10
lrwxrwxrwx root    root              2014-01-11 04:52 persdata -> /dev/block/mm
cblk0p22
lrwxrwxrwx root    root              2014-01-11 04:52 persist -> /dev/block/mmc
blk0p21
lrwxrwxrwx root    root              2014-01-11 04:52 recovery -> /dev/block/mm
cblk0p15
lrwxrwxrwx root    root              2014-01-11 04:52 rpm -> /dev/block/mmcblk0
p7
lrwxrwxrwx root    root              2014-01-11 04:52 sbl1 -> /dev/block/mmcblk
0p3
lrwxrwxrwx root    root              2014-01-11 04:52 ssd -> /dev/block/mmcblk0
p20
lrwxrwxrwx root    root              2014-01-11 04:52 system -> /dev/block/mmcb
lk0p23
lrwxrwxrwx root    root              2014-01-11 04:52 tz -> /dev/block/mmcblk0p
8
lrwxrwxrwx root    root              2014-01-11 04:52 userdata -> /dev/block/mm
cblk0p26

---

And I backup with :
dd if=/dev/block/platform/msm_sdcc.1/mmcblk0p10 of=/storage/extSdCard/param.bin bs=4096

But when I opened param.bin with tar was empty.

Any idea?